diff --git a/app/admin/competitions/competition-row.tsx b/app/admin/competitions/competition-row.tsx
index 5240896e..36f57e3a 100644
--- a/app/admin/competitions/competition-row.tsx
+++ b/app/admin/competitions/competition-row.tsx
@@ -19,6 +19,7 @@ import {
 import { CreateEditCompetitionForm } from "@/components/forms/create-edit-competition-form";
 import { useState } from "react";
 import { formatDate, formatDateTime } from "@/lib/time-utils";
+import { getBrowserTimezone } from "@/hooks/getBrowserTimezone";
 import { CompetitionStatusBadge } from "./competition-status-badge";
 import { getCompetitionStatusFromObject } from "@/lib/competition-status";
 
@@ -32,6 +33,7 @@ export default function CompetitionRow({
   nResolvedProps: number;
 }) {
   const [open, setOpen] = useState(false);
+  const timezone = getBrowserTimezone();
 
   const status = getCompetitionStatusFromObject(competition);
 
@@ -84,22 +86,22 @@ export default function CompetitionRow({
                       competition.forecasts_open_date && (
                         <>
                           Forecasts open{" "}
-                          {formatDate(competition.forecasts_open_date)}
+                          {formatDate(competition.forecasts_open_date, timezone)}
                         </>
                       )}
                     {status === "forecasts-open" &&
                       competition.forecasts_close_date && (
                         <>
                           Forecasts close{" "}
-                          {formatDate(competition.forecasts_close_date)}
+                          {formatDate(competition.forecasts_close_date, timezone)}
                         </>
                       )}
                     {status === "forecasts-closed" &&
                       competition.end_date && (
-                        <>Ends {formatDate(competition.end_date)}</>
+                        <>Ends {formatDate(competition.end_date, timezone)}</>
                       )}
                     {status === "ended" && competition.end_date && (
-                      <>Ended {formatDate(competition.end_date)}</>
+                      <>Ended {formatDate(competition.end_date, timezone)}</>
                     )}
                     {status === "private" && (
                       <>Uses per-prop deadlines</>
@@ -114,17 +116,17 @@ export default function CompetitionRow({
                       {competition.forecasts_open_date && (
                         <p>
                           Forecasts Open:{" "}
-                          {formatDateTime(competition.forecasts_open_date)}
+                          {formatDateTime(competition.forecasts_open_date, timezone)}
                         </p>
                       )}
                       {competition.forecasts_close_date && (
                         <p>
                           Forecasts Close:{" "}
-                          {formatDateTime(competition.forecasts_close_date)}
+                          {formatDateTime(competition.forecasts_close_date, timezone)}
                         </p>
                       )}
                       {competition.end_date && (
-                        <p>Ends: {formatDateTime(competition.end_date)}</p>
+                        <p>Ends: {formatDateTime(competition.end_date, timezone)}</p>
                       )}
                     </div>
                   )}
diff --git a/app/admin/users/[userId]/user-detail-card.tsx b/app/admin/users/[userId]/user-detail-card.tsx
index 4e45a86b..70e282f7 100644
--- a/app/admin/users/[userId]/user-detail-card.tsx
+++ b/app/admin/users/[userId]/user-detail-card.tsx
@@ -14,8 +14,9 @@ import {
   DialogTrigger,
 } from "@/components/ui/dialog";
 import { Copy, Shield, User, UserCheck, UserX } from "lucide-react";
-import { format } from "date-fns";
 import { setUserActive } from "@/lib/db_actions/users";
+import { getBrowserTimezone } from "@/hooks/getBrowserTimezone";
+import { formatDate, formatDateTime } from "@/lib/time-utils";
 import { startImpersonation } from "@/lib/auth/impersonation";
 import { handleServerActionResult } from "@/lib/server-action-helpers";
 import { toast } from "@/hooks/use-toast";
@@ -32,6 +33,7 @@ export default function UserDetailCard({ user }: UserDetailCardProps) {
   const [isImpersonateDialogOpen, setIsImpersonateDialogOpen] = useState(false);
   const [isLoading, setIsLoading] = useState(false);
   const router = useRouter();
+  const timezone = getBrowserTimezone();
   const isActive = user.deactivated_at === null;
   const canImpersonate = !user.is_admin && isActive;
 
@@ -191,7 +193,7 @@ export default function UserDetailCard({ user }: UserDetailCardProps) {
                 Created
               </span>
               <span className="text-sm">
-                {format(new Date(user.created_at), "MMM d, yyyy")}
+                {formatDate(new Date(user.created_at), timezone)}
               </span>
             </div>
 
@@ -200,7 +202,7 @@ export default function UserDetailCard({ user }: UserDetailCardProps) {
                 Updated
               </span>
               <span className="text-sm">
-                {format(new Date(user.updated_at), "MMM d, yyyy")}
+                {formatDate(new Date(user.updated_at), timezone)}
               </span>
             </div>
 
@@ -210,10 +212,7 @@ export default function UserDetailCard({ user }: UserDetailCardProps) {
                   Deactivated
                 </span>
                 <span className="text-sm">
-                  {format(
-                    new Date(user.deactivated_at),
-                    "MMM d, yyyy 'at' h:mm a",
-                  )}
+                  {formatDateTime(new Date(user.deactivated_at), timezone)}
                 </span>
               </div>
             )}
diff --git a/app/competitions/[competitionId]/competition-start-end.tsx b/app/competitions/[competitionId]/competition-start-end.tsx
index 136a9dd1..dce95f1a 100644
--- a/app/competitions/[competitionId]/competition-start-end.tsx
+++ b/app/competitions/[competitionId]/competition-start-end.tsx
@@ -1,16 +1,16 @@
 "use client";
 
 import { Competition } from "@/types/db_types";
-import { formatInTimeZone } from "date-fns-tz";
 import { getCompetitionStatusFromObject } from "@/lib/competition-status";
-
-const DATE_FORMAT = "MMM d, yyyy";
+import { getBrowserTimezone } from "@/hooks/getBrowserTimezone";
+import { formatDate } from "@/lib/time-utils";
 
 export default function CompetitionStartEnd({
   competition,
 }: {
   competition: Competition;
 }) {
+  const timezone = getBrowserTimezone();
   const status = getCompetitionStatusFromObject(competition);
   return (
     <div className="flex flex-row flex-wrap items-center justify-start gap-x-4 sm:gap-x-8 gap-y-2 mb-4 text-sm">
@@ -20,19 +20,11 @@ export default function CompetitionStartEnd({
           <>
             <p>
               <span className="text-muted-foreground">Forecasts open</span>{" "}
-              {formatInTimeZone(
-                competition.forecasts_open_date,
-                "UTC",
-                DATE_FORMAT,
-              )}
+              {formatDate(competition.forecasts_open_date, timezone)}
             </p>
             <p>
               <span className="text-muted-foreground">Forecasts close</span>{" "}
-              {formatInTimeZone(
-                competition.forecasts_close_date,
-                "UTC",
-                DATE_FORMAT,
-              )}
+              {formatDate(competition.forecasts_close_date, timezone)}
             </p>
           </>
         )}
@@ -42,19 +34,11 @@ export default function CompetitionStartEnd({
           <>
             <p>
               <span className="text-muted-foreground">Forecasts opened</span>{" "}
-              {formatInTimeZone(
-                competition.forecasts_open_date,
-                "UTC",
-                DATE_FORMAT,
-              )}
+              {formatDate(competition.forecasts_open_date, timezone)}
             </p>
             <p>
               <span className="text-muted-foreground">Forecasts close</span>{" "}
-              {formatInTimeZone(
-                competition.forecasts_close_date,
-                "UTC",
-                DATE_FORMAT,
-              )}
+              {formatDate(competition.forecasts_close_date, timezone)}
             </p>
           </>
         )}
@@ -64,22 +48,18 @@ export default function CompetitionStartEnd({
           <>
             <p>
               <span className="text-muted-foreground">Forecasts closed</span>{" "}
-              {formatInTimeZone(
-                competition.forecasts_close_date,
-                "UTC",
-                DATE_FORMAT,
-              )}
+              {formatDate(competition.forecasts_close_date, timezone)}
             </p>
             <p>
               <span className="text-muted-foreground">Competition Ends</span>{" "}
-              {formatInTimeZone(competition.end_date, "UTC", DATE_FORMAT)}
+              {formatDate(competition.end_date, timezone)}
             </p>
           </>
         )}
       {status === "ended" && competition.end_date && (
         <p>
           <span className="text-muted-foreground">Ended</span>{" "}
-          {formatInTimeZone(competition.end_date, "UTC", DATE_FORMAT)}
+          {formatDate(competition.end_date, timezone)}
         </p>
       )}
       {status === "private" && (
diff --git a/app/competitions/[competitionId]/props/[propId]/competition-prop-view.tsx b/app/competitions/[competitionId]/props/[propId]/competition-prop-view.tsx
index 84420578..93511910 100644
--- a/app/competitions/[competitionId]/props/[propId]/competition-prop-view.tsx
+++ b/app/competitions/[competitionId]/props/[propId]/competition-prop-view.tsx
@@ -10,10 +10,12 @@ import { Button } from "@/components/ui/button";
 import { Card, CardContent } from "@/components/ui/card";
 import { MarkdownRenderer } from "@/components/markdown";
 import { useCurrentUser } from "@/hooks/useCurrentUser";
+import { getBrowserTimezone } from "@/hooks/getBrowserTimezone";
 import { createForecast, updateForecast } from "@/lib/db_actions";
 import { useServerAction } from "@/hooks/use-server-action";
 import { Spinner } from "@/components/ui/spinner";
 import { PropEditDialog } from "@/components/dialogs/prop-edit-dialog";
+import { formatDateTime } from "@/lib/time-utils";
 
 interface CompetitionPropViewProps {
   prop: PropWithUserForecast;
@@ -68,17 +70,10 @@ const getProbColor = (prob: number | null) => {
   };
 };
 
-function formatDate(date: Date | string | null): string {
+function formatPropDate(date: Date | string | null, timezone: string): string {
   if (!date) return "No deadline";
   const d = typeof date === "string" ? new Date(date) : date;
-  return d.toLocaleDateString("en-US", {
-    weekday: "short",
-    month: "short",
-    day: "numeric",
-    year: "numeric",
-    hour: "numeric",
-    minute: "2-digit",
-  });
+  return formatDateTime(d, timezone);
 }
 
 function getRelativeDeadline(date: Date | string | null): string | null {
@@ -104,6 +99,7 @@ export function CompetitionPropView({
 }: CompetitionPropViewProps) {
   const router = useRouter();
   const { user } = useCurrentUser();
+  const timezone = getBrowserTimezone();
   const [localForecast, setLocalForecast] = useState<number | null>(
     prop.user_forecast,
   );
@@ -235,7 +231,7 @@ export function CompetitionPropView({
           <div className="flex flex-wrap items-center gap-4 mt-4 text-sm">
             <div className="flex items-center gap-2 text-muted-foreground">
               <CalendarClock className="h-4 w-4" />
-              <span>Forecasts due: {formatDate(prop.prop_forecasts_due_date)}</span>
+              <span>Forecasts due: {formatPropDate(prop.prop_forecasts_due_date, timezone)}</span>
               {relativeDeadline && (
                 <Badge
                   variant={relativeDeadline === "Closed" ? "destructive" : "outline"}
@@ -248,7 +244,7 @@ export function CompetitionPropView({
             {prop.prop_resolution_due_date && (
               <div className="flex items-center gap-2 text-muted-foreground">
                 <Calendar className="h-4 w-4" />
-                <span>Resolves: {formatDate(prop.prop_resolution_due_date)}</span>
+                <span>Resolves: {formatPropDate(prop.prop_resolution_due_date, timezone)}</span>
               </div>
             )}
           </div>
diff --git a/app/competitions/[competitionId]/props/new/new-prop-form.tsx b/app/competitions/[competitionId]/props/new/new-prop-form.tsx
index ded153cb..88d1410b 100644
--- a/app/competitions/[competitionId]/props/new/new-prop-form.tsx
+++ b/app/competitions/[competitionId]/props/new/new-prop-form.tsx
@@ -40,7 +40,9 @@ import { Card, CardContent } from "@/components/ui/card";
 import { DateTimePicker } from "@/components/ui/date-time-picker";
 import { Spinner } from "@/components/ui/spinner";
 import { useServerAction } from "@/hooks/use-server-action";
+import { getBrowserTimezone } from "@/hooks/getBrowserTimezone";
 import { createProp } from "@/lib/db_actions";
+import { formatDate } from "@/lib/time-utils";
 import type { Category } from "@/types/db_types";
 
 const formSchema = z
@@ -100,6 +102,7 @@ export function NewPropForm({
   userId,
 }: NewPropFormProps) {
   const router = useRouter();
+  const timezone = getBrowserTimezone();
   const [showPreview, setShowPreview] = useState(false);
 
   const form = useForm<FormValues>({
@@ -346,7 +349,7 @@ export function NewPropForm({
                   {watchedForecastsDueDate && (
                     <p className="text-xs text-muted-foreground">
                       Forecasts due:{" "}
-                      {watchedForecastsDueDate.toLocaleDateString()}
+                      {formatDate(watchedForecastsDueDate, timezone)}
                     </p>
                   )}
                 </div>
diff --git a/app/competitions/page.tsx b/app/competitions/page.tsx
index aad40449..c2bdbdff 100644
--- a/app/competitions/page.tsx
+++ b/app/competitions/page.tsx
@@ -12,7 +12,7 @@ import {
 import { Button } from "@/components/ui/button";
 import { Trophy, BarChart3, List } from "lucide-react";
 import { CompetitionStatusBadge } from "@/app/admin/competitions/competition-status-badge";
-import { formatDate } from "@/lib/time-utils";
+import { LocalDate } from "@/components/local-date";
 import { getCompetitionStatusFromObject } from "@/lib/competition-status";
 
 export default async function CompetitionsPage() {
@@ -74,13 +74,13 @@ export default async function CompetitionsPage() {
                               <span className="font-medium">
                                 Forecasts due:
                               </span>{" "}
-                              {formatDate(competition.forecasts_close_date)}
+                              <LocalDate date={competition.forecasts_close_date} />
                             </p>
                           )}
                           {competition.end_date && (
                             <p>
                               <span className="font-medium">Ends:</span>{" "}
-                              {formatDate(competition.end_date)}
+                              <LocalDate date={competition.end_date} />
                             </p>
                           )}
                         </>
@@ -133,13 +133,13 @@ export default async function CompetitionsPage() {
                               <span className="font-medium">
                                 Forecasts due:
                               </span>{" "}
-                              {formatDate(competition.forecasts_close_date)}
+                              <LocalDate date={competition.forecasts_close_date} />
                             </p>
                           )}
                           {competition.end_date && (
                             <p>
                               <span className="font-medium">Ends:</span>{" "}
-                              {formatDate(competition.end_date)}
+                              <LocalDate date={competition.end_date} />
                             </p>
                           )}
                         </>
diff --git a/components/competition-dashboard/upcoming-deadlines.tsx b/components/competition-dashboard/upcoming-deadlines.tsx
index f59166a1..920b7323 100644
--- a/components/competition-dashboard/upcoming-deadlines.tsx
+++ b/components/competition-dashboard/upcoming-deadlines.tsx
@@ -3,6 +3,8 @@
 import Link from "next/link";
 import { cn } from "@/lib/utils";
 import type { UpcomingDeadline } from "@/lib/db_actions/competition-stats";
+import { getBrowserTimezone } from "@/hooks/getBrowserTimezone";
+import { formatDate } from "@/lib/time-utils";
 
 interface DeadlineDisplay {
   text: string;
@@ -10,16 +12,12 @@ interface DeadlineDisplay {
   urgent: boolean;
 }
 
-function formatDeadline(date: Date): DeadlineDisplay {
+function formatDeadline(date: Date, timezone: string): DeadlineDisplay {
   const now = new Date();
   const diffMs = date.getTime() - now.getTime();
   const diffDays = Math.ceil(diffMs / (1000 * 60 * 60 * 24));
 
-  const formatted = date.toLocaleDateString("en-US", {
-    month: "short",
-    day: "numeric",
-    year: date.getFullYear() !== now.getFullYear() ? "numeric" : undefined,
-  });
+  const formatted = formatDate(date, timezone);
 
   if (diffDays <= 0) {
     return { text: formatted, relative: "Overdue", urgent: true };
@@ -73,10 +71,11 @@ function getProbColor(prob: number | null): { bg: string; text: string } {
 interface UpcomingPropRowProps {
   prop: UpcomingDeadline;
   competitionId: number;
+  timezone: string;
 }
 
-function UpcomingPropRow({ prop, competitionId }: UpcomingPropRowProps) {
-  const deadline = formatDeadline(prop.deadline);
+function UpcomingPropRow({ prop, competitionId, timezone }: UpcomingPropRowProps) {
+  const deadline = formatDeadline(prop.deadline, timezone);
   const colors = getProbColor(prop.userForecast);
   const percent =
     prop.userForecast !== null ? Math.round(prop.userForecast * 100) : null;
@@ -140,6 +139,8 @@ export function UpcomingDeadlines({
   competitionId,
   onViewAll,
 }: UpcomingDeadlinesProps) {
+  const timezone = getBrowserTimezone();
+
   if (deadlines.length === 0) {
     return (
       <div className="bg-card border border-border rounded-lg p-5">
@@ -173,6 +174,7 @@ export function UpcomingDeadlines({
             key={prop.propId}
             prop={prop}
             competitionId={competitionId}
+            timezone={timezone}
           />
         ))}
       </div>
diff --git a/components/landing/resolved-prop-card.tsx b/components/landing/resolved-prop-card.tsx
index 8fc66b6d..43b9913f 100644
--- a/components/landing/resolved-prop-card.tsx
+++ b/components/landing/resolved-prop-card.tsx
@@ -1,6 +1,7 @@
 import { Card, CardContent } from "@/components/ui/card";
 import { CheckCircle, XCircle } from "lucide-react";
 import Link from "next/link";
+import { LocalDate } from "@/components/local-date";
 
 interface ResolvedPropCardProps {
   propId: number;
@@ -11,10 +12,6 @@ interface ResolvedPropCardProps {
   resolutionDate: Date;
 }
 
-function formatShortDate(date: Date): string {
-  return date.toLocaleDateString("en-US", { month: "short", day: "numeric" });
-}
-
 export default function ResolvedPropCard({
   propId,
   propText,
@@ -57,7 +54,7 @@ export default function ResolvedPropCard({
                   <XCircle className="h-5 w-5 text-red-600" />
                 )}
                 <span className="text-sm text-muted-foreground">
-                  {formatShortDate(resolutionDate)}
+                  <LocalDate date={resolutionDate} />
                 </span>
               </div>
             </div>
diff --git a/components/local-date.tsx b/components/local-date.tsx
new file mode 100644
index 00000000..b6c6b60b
--- /dev/null
+++ b/components/local-date.tsx
@@ -0,0 +1,18 @@
+"use client";
+
+import { formatDate, formatDateTime } from "@/lib/time-utils";
+import { getBrowserTimezone } from "@/hooks/getBrowserTimezone";
+
+interface LocalDateProps {
+  date: Date;
+  includeTime?: boolean;
+}
+
+export function LocalDate({ date, includeTime = false }: LocalDateProps) {
+  const timezone = getBrowserTimezone();
+  return (
+    <span suppressHydrationWarning>
+      {includeTime ? formatDateTime(date, timezone) : formatDate(date, timezone)}
+    </span>
+  );
+}
diff --git a/hooks/getBrowserTimezone.ts b/hooks/getBrowserTimezone.ts
new file mode 100644
index 00000000..f2e8a3eb
--- /dev/null
+++ b/hooks/getBrowserTimezone.ts
@@ -0,0 +1,12 @@
+"use client";
+
+const DEFAULT_TIMEZONE = "UTC";
+
+export function getBrowserTimezone(): string {
+  if (typeof window === "undefined") return DEFAULT_TIMEZONE;
+  try {
+    return Intl.DateTimeFormat().resolvedOptions().timeZone;
+  } catch {
+    return DEFAULT_TIMEZONE;
+  }
+}
diff --git a/lib/time-utils.test.ts b/lib/time-utils.test.ts
new file mode 100644
index 00000000..1bf2cac9
--- /dev/null
+++ b/lib/time-utils.test.ts
@@ -0,0 +1,37 @@
+import { describe, it, expect } from "vitest";
+import { formatDate, formatDateTime } from "./time-utils";
+
+describe("formatDate", () => {
+  const testDate = new Date("2025-01-15T17:00:00Z");
+
+  it("should format date in UTC by default", () => {
+    const result = formatDate(testDate);
+    expect(result).toContain("Jan");
+    expect(result).toContain("15");
+    expect(result).toContain("2025");
+  });
+
+  it("should format date in specified timezone", () => {
+    // 5pm UTC = 12pm Eastern (UTC-5)
+    const result = formatDate(testDate, "America/New_York");
+    expect(result).toContain("Jan");
+    expect(result).toContain("15");
+  });
+});
+
+describe("formatDateTime", () => {
+  const testDate = new Date("2025-01-15T17:00:00Z");
+
+  it("should format datetime in UTC by default with UTC label", () => {
+    const result = formatDateTime(testDate);
+    expect(result).toContain("17:00");
+    expect(result).toContain("UTC");
+  });
+
+  it("should format datetime in specified timezone with timezone label", () => {
+    const result = formatDateTime(testDate, "America/New_York");
+    expect(result).toContain("12:00");
+    // Check for timezone indicator (could be EST, EDT, or full name)
+    expect(result).toMatch(/EST|EDT|Eastern/);
+  });
+});
diff --git a/lib/time-utils.ts b/lib/time-utils.ts
index e4dcb9c5..08521181 100644
--- a/lib/time-utils.ts
+++ b/lib/time-utils.ts
@@ -1,13 +1,18 @@
+const DEFAULT_TIMEZONE = "UTC";
+
 /**
  * Format a date for display (date only)
  * Uses browser locale for proper internationalization
  */
-export function formatDate(date: Date): string {
+export function formatDate(
+  date: Date,
+  timezone: string = DEFAULT_TIMEZONE
+): string {
   return new Intl.DateTimeFormat(undefined, {
     month: "short",
     day: "numeric",
     year: "numeric",
-    timeZone: "UTC",
+    timeZone: timezone,
   }).format(date);
 }
 
@@ -15,20 +20,31 @@ export function formatDate(date: Date): string {
  * Format a full datetime for tooltips
  * Uses browser locale for proper internationalization with 24-hour time
  */
-export function formatDateTime(date: Date): string {
+export function formatDateTime(
+  date: Date,
+  timezone: string = DEFAULT_TIMEZONE
+): string {
   const dateStr = new Intl.DateTimeFormat(undefined, {
     month: "short",
     day: "numeric",
     year: "numeric",
-    timeZone: "UTC",
+    timeZone: timezone,
   }).format(date);
 
   const timeStr = new Intl.DateTimeFormat(undefined, {
     hour: "2-digit",
     minute: "2-digit",
     hour12: false,
-    timeZone: "UTC",
+    timeZone: timezone,
   }).format(date);
 
-  return `${dateStr} at ${timeStr} UTC`;
+  // Get the timezone abbreviation (e.g., EST, PST, UTC)
+  const tzAbbr = new Intl.DateTimeFormat(undefined, {
+    timeZoneName: "short",
+    timeZone: timezone,
+  })
+    .formatToParts(date)
+    .find((part) => part.type === "timeZoneName")?.value ?? timezone;
+
+  return `${dateStr} at ${timeStr} ${tzAbbr}`;
 }