diff --git a/frontend_tests/node_tests/people.js b/frontend_tests/node_tests/people.js
index df4ab3784f..53c8fcd0b6 100644
--- a/frontend_tests/node_tests/people.js
+++ b/frontend_tests/node_tests/people.js
@@ -3,7 +3,6 @@
 const {strict: assert} = require("assert");
 
 const {parseISO} = require("date-fns");
-const date_fns_tz = require("date-fns-tz");
 const _ = require("lodash");
 const MockDate = require("mockdate");
 
@@ -520,14 +519,10 @@ test_people("utcToZonedTime", ({override}) => {
     MockDate.set(parseISO("20130208T080910").getTime());
     user_settings.twenty_four_hour_time = true;
 
-    override(date_fns_tz, "utcToZonedTime", () => new Date("2022/10/10 03:24"));
-    assert.equal(people.get_user_time(me.user_id), "3:24");
+    assert.equal(people.get_user_time(me.user_id), "0:09");
 
-    override(date_fns_tz, "utcToZonedTime", () => new Date("foo"));
-    blueslip.expect("error", "Got invalid date for timezone: America/Los_Angeles", 2);
-    people.get_user_time(me.user_id);
-
-    override(date_fns_tz, "utcToZonedTime", () => undefined);
+    override(people.get_by_user_id(me.user_id), "timezone", "Eriador/Rivendell");
+    blueslip.expect("error", "Got invalid date for timezone: Eriador/Rivendell");
     people.get_user_time(me.user_id);
 });
 
diff --git a/static/js/people.js b/static/js/people.js
index c09be6d64e..1bd8ee9c0a 100644
--- a/static/js/people.js
+++ b/static/js/people.js
@@ -287,14 +287,8 @@ export function get_user_time(user_id) {
     const user_pref = get_user_time_preferences(user_id);
     if (user_pref) {
         const current_date = utcToZonedTime(new Date(), user_pref.timezone);
-        // In theory, utcToZonedTime should always return a Date
-        // object. However, we have reports from users in the wild
-        // seeing this returning `undefined`. To avoid throwing an
-        // exception, we check whether we got a Date object back,
-        // including a NaN check, which covers the case where we
-        // called `Date("foo")`.
-        // eslint-disable-next-line unicorn/prefer-number-properties
-        if (!(current_date instanceof Date) || isNaN(current_date)) {
+        // This could happen if the timezone is invalid.
+        if (Number.isNaN(current_date.getTime())) {
             blueslip.error(`Got invalid date for timezone: ${user_pref.timezone}`);
             return undefined;
         }