diff --git a/apps/web/lib/clock.ts b/apps/web/lib/clock.ts
index 3551c53f6a..7c44f96dc9 100644
--- a/apps/web/lib/clock.ts
+++ b/apps/web/lib/clock.ts
@@ -1,5 +1,5 @@
 // handles logic related to user clock display using 24h display / timeZone options.
-import dayjs from "@calcom/dayjs";
+import { CURRENT_TIMEZONE } from "@calcom/lib/constants";
 import {
   getIs24hClockFromLocalStorage,
   isBrowserLocale24h,
@@ -26,8 +26,7 @@ const initClock = () => {
   // This only sets browser locale if there's no preference on localStorage.
   if (getIs24hClockFromLocalStorage() === null) set24hClock(isBrowserLocale24h());
   timeOptions.is24hClock = !!getIs24hClockFromLocalStorage();
-  timeOptions.inviteeTimeZone =
-    localStorage.getItem("timeOption.preferredTimeZone") || dayjs.tz.guess() || "Europe/London";
+  timeOptions.inviteeTimeZone = localStorage.getItem("timeOption.preferredTimeZone") || CURRENT_TIMEZONE;
 };
 
 const is24h = (is24hClock?: boolean) => {
diff --git a/apps/web/modules/bookings/views/bookings-single-view.test.tsx b/apps/web/modules/bookings/views/bookings-single-view.test.tsx
index 9a2705626f..24a3d3ff51 100644
--- a/apps/web/modules/bookings/views/bookings-single-view.test.tsx
+++ b/apps/web/modules/bookings/views/bookings-single-view.test.tsx
@@ -103,6 +103,13 @@ describe("Success Component", () => {
     vi.mocked(useRouterQuery).mockReturnValue({
       uid: "uid",
     });
+    vi.mock("@calcom/lib/constants", async (importOriginal) => {
+      const actual = await importOriginal<any>();
+      return {
+        ...actual,
+        CURRENT_TIMEZONE: "Europe/London",
+      };
+    });
     vi.mocked(useSession).mockReturnValue({
       update: vi.fn(),
       status: "authenticated",
diff --git a/apps/web/modules/bookings/views/bookings-single-view.tsx b/apps/web/modules/bookings/views/bookings-single-view.tsx
index 623171b712..0f7662717b 100644
--- a/apps/web/modules/bookings/views/bookings-single-view.tsx
+++ b/apps/web/modules/bookings/views/bookings-single-view.tsx
@@ -31,7 +31,7 @@ import {
   SystemField,
   TITLE_FIELD,
 } from "@calcom/features/bookings/lib/SystemField";
-import { APP_NAME } from "@calcom/lib/constants";
+import { APP_NAME, CURRENT_TIMEZONE } from "@calcom/lib/constants";
 import {
   formatToLocalizedDate,
   formatToLocalizedTime,
@@ -258,9 +258,7 @@ export default function Success(props: PageProps) {
   }, [telemetry]); */
 
   useEffect(() => {
-    setDate(
-      date.tz(localStorage.getItem("timeOption.preferredTimeZone") || dayjs.tz.guess() || "Europe/London")
-    );
+    setDate(date.tz(localStorage.getItem("timeOption.preferredTimeZone") || CURRENT_TIMEZONE));
     setIs24h(props?.userTimeFormat ? props.userTimeFormat === 24 : !!getIs24hClockFromLocalStorage());
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [eventType, needsConfirmation]);
diff --git a/packages/features/bookings/lib/timePreferences.ts b/packages/features/bookings/lib/timePreferences.ts
index 7619685622..4eeb742fee 100644
--- a/packages/features/bookings/lib/timePreferences.ts
+++ b/packages/features/bookings/lib/timePreferences.ts
@@ -1,6 +1,6 @@
 import { create } from "zustand";
 
-import dayjs from "@calcom/dayjs";
+import { CURRENT_TIMEZONE } from "@calcom/lib/constants";
 import { TimeFormat, detectBrowserTimeFormat, setIs24hClockInLocalStorage } from "@calcom/lib/timeFormat";
 import { localStorage } from "@calcom/lib/webstorage";
 
@@ -24,7 +24,7 @@ export const timePreferencesStore = create<TimePreferencesStore>((set) => ({
     setIs24hClockInLocalStorage(format === TimeFormat.TWENTY_FOUR_HOUR);
     set({ timeFormat: format });
   },
-  timezone: localStorage.getItem(timezoneLocalStorageKey) || dayjs.tz.guess() || "Europe/London",
+  timezone: localStorage.getItem(timezoneLocalStorageKey) || CURRENT_TIMEZONE,
   setTimezone: (timezone: string) => {
     localStorage.setItem(timezoneLocalStorageKey, timezone);
     set({ timezone });
diff --git a/packages/features/ee/payments/components/PaymentPage.tsx b/packages/features/ee/payments/components/PaymentPage.tsx
index 36a9f9320f..626acdafcd 100644
--- a/packages/features/ee/payments/components/PaymentPage.tsx
+++ b/packages/features/ee/payments/components/PaymentPage.tsx
@@ -11,7 +11,7 @@ import dayjs from "@calcom/dayjs";
 import { sdkActionManager, useIsEmbed } from "@calcom/embed-core/embed-iframe";
 import { PayIcon } from "@calcom/features/bookings/components/event-meta/PayIcon";
 import { Price } from "@calcom/features/bookings/components/event-meta/Price";
-import { APP_NAME, WEBSITE_URL } from "@calcom/lib/constants";
+import { APP_NAME, WEBSITE_URL, CURRENT_TIMEZONE } from "@calcom/lib/constants";
 import getPaymentAppData from "@calcom/lib/getPaymentAppData";
 import { useLocale } from "@calcom/lib/hooks/useLocale";
 import useTheme from "@calcom/lib/hooks/useTheme";
@@ -51,8 +51,7 @@ const PaymentPage: FC<PaymentPageProps> = (props) => {
   const paymentAppData = getPaymentAppData(props.eventType);
   useEffect(() => {
     let embedIframeWidth = 0;
-    const _timezone =
-      localStorage.getItem("timeOption.preferredTimeZone") || dayjs.tz.guess() || "Europe/London";
+    const _timezone = localStorage.getItem("timeOption.preferredTimeZone") || CURRENT_TIMEZONE;
     setTimezone(_timezone);
     setDate(date.tz(_timezone));
     setIs24h(!!getIs24hClockFromLocalStorage());
diff --git a/packages/features/ee/teams/components/TeamAvailabilityModal.tsx b/packages/features/ee/teams/components/TeamAvailabilityModal.tsx
index a39d300358..48003c5e5b 100644
--- a/packages/features/ee/teams/components/TeamAvailabilityModal.tsx
+++ b/packages/features/ee/teams/components/TeamAvailabilityModal.tsx
@@ -2,7 +2,7 @@ import { useEffect, useState } from "react";
 
 import dayjs from "@calcom/dayjs";
 import LicenseRequired from "@calcom/features/ee/common/components/LicenseRequired";
-import { WEBAPP_URL } from "@calcom/lib/constants";
+import { WEBAPP_URL, CURRENT_TIMEZONE } from "@calcom/lib/constants";
 import { useLocale } from "@calcom/lib/hooks/useLocale";
 import type { RouterOutputs } from "@calcom/trpc/react";
 import { trpc } from "@calcom/trpc/react";
@@ -20,7 +20,7 @@ export default function TeamAvailabilityModal(props: Props) {
   const utils = trpc.useUtils();
   const [selectedDate, setSelectedDate] = useState(dayjs());
   const [selectedTimeZone, setSelectedTimeZone] = useState<ITimezone>(
-    localStorage.getItem("timeOption.preferredTimeZone") || dayjs.tz.guess() || "Europe/London"
+    localStorage.getItem("timeOption.preferredTimeZone") || CURRENT_TIMEZONE
   );
 
   const { t } = useLocale();
diff --git a/packages/features/settings/TimezoneChangeDialog.tsx b/packages/features/settings/TimezoneChangeDialog.tsx
index 2b2d849340..5df01f612d 100644
--- a/packages/features/settings/TimezoneChangeDialog.tsx
+++ b/packages/features/settings/TimezoneChangeDialog.tsx
@@ -5,6 +5,7 @@ import { useSession } from "next-auth/react";
 import { useEffect, useState } from "react";
 
 import dayjs from "@calcom/dayjs";
+import { CURRENT_TIMEZONE } from "@calcom/lib/constants";
 import { useLocale } from "@calcom/lib/hooks/useLocale";
 import { trpc } from "@calcom/trpc/react";
 import { showToast, Dialog, DialogClose, DialogContent, DialogFooter, DialogHeader } from "@calcom/ui";
@@ -22,8 +23,7 @@ const TimezoneChangeDialogContent = () => {
 
   const utils = trpc.useUtils();
 
-  const browserTimezone = dayjs.tz.guess() || "Europe/London";
-  const formattedCurrentTz = browserTimezone.replace("_", " ");
+  const formattedCurrentTz = CURRENT_TIMEZONE.replace("_", " ");
 
   const onMutationSuccess = async () => {
     showToast(t("updated_timezone_to", { formattedCurrentTz }), "success");
@@ -42,7 +42,7 @@ const TimezoneChangeDialogContent = () => {
 
   const updateTimezone = () => {
     mutation.mutate({
-      timeZone: browserTimezone,
+      timeZone: CURRENT_TIMEZONE,
     });
   };
 
@@ -77,8 +77,10 @@ export function useOpenTimezoneDialog() {
     if (!user?.timeZone || status !== "authenticated" || userSession?.user?.impersonatedBy) {
       return;
     }
-    const browserTimezone = dayjs.tz.guess() || "Europe/London";
-    if (dayjs.tz(undefined, browserTimezone).utcOffset() !== dayjs.tz(undefined, user.timeZone).utcOffset()) {
+
+    if (
+      dayjs.tz(undefined, CURRENT_TIMEZONE).utcOffset() !== dayjs.tz(undefined, user.timeZone).utcOffset()
+    ) {
       setShowDialog(true);
     }
   }, [user?.timeZone, status, userSession?.user?.impersonatedBy]);
diff --git a/packages/features/timezone-buddy/components/AvailabilitySliderTable.tsx b/packages/features/timezone-buddy/components/AvailabilitySliderTable.tsx
index 2050589d9a..a3ad8221c8 100644
--- a/packages/features/timezone-buddy/components/AvailabilitySliderTable.tsx
+++ b/packages/features/timezone-buddy/components/AvailabilitySliderTable.tsx
@@ -8,6 +8,7 @@ import { useCallback, useEffect, useMemo, useRef, useState } from "react";
 import dayjs from "@calcom/dayjs";
 import { DataTable, DataTableToolbar } from "@calcom/features/data-table";
 import { APP_NAME, WEBAPP_URL } from "@calcom/lib/constants";
+import { CURRENT_TIMEZONE } from "@calcom/lib/constants";
 import type { DateRange } from "@calcom/lib/date-ranges";
 import { useDebounce } from "@calcom/lib/hooks/useDebounce";
 import { useLocale } from "@calcom/lib/hooks/useLocale";
@@ -78,7 +79,7 @@ export function AvailabilitySliderTable(props: { userTimeFormat: number | null;
   const { data, isPending, fetchNextPage, isFetching } = trpc.viewer.availability.listTeam.useInfiniteQuery(
     {
       limit: 10,
-      loggedInUsersTz: dayjs.tz.guess() || "Europe/London",
+      loggedInUsersTz: CURRENT_TIMEZONE,
       startDate: browsingDate.startOf("day").toISOString(),
       endDate: browsingDate.endOf("day").toISOString(),
       searchString: debouncedSearchString,
diff --git a/packages/lib/constants.ts b/packages/lib/constants.ts
index 95a6db6ff4..b87396279c 100644
--- a/packages/lib/constants.ts
+++ b/packages/lib/constants.ts
@@ -65,6 +65,8 @@ export const HOSTED_CAL_FEATURES = process.env.NEXT_PUBLIC_HOSTED_CAL_FEATURES |
 
 export const IS_EUROPE = dayjs.tz.guess()?.indexOf("Europe") !== -1;
 
+export const CURRENT_TIMEZONE = dayjs.tz.guess() !== "Etc/Unknown" ? dayjs.tz.guess() : "Europe/London";
+
 /** @deprecated use `WEBAPP_URL` */
 export const NEXT_PUBLIC_BASE_URL = process.env.NEXT_PUBLIC_WEBAPP_URL || `https://${process.env.VERCEL_URL}`;
 export const LOGO = "/calcom-logo-white-word.svg";
diff --git a/packages/platform/atoms/event-types/payments/PaymentForm.tsx b/packages/platform/atoms/event-types/payments/PaymentForm.tsx
index 73d9d4befa..bb3f8411c6 100644
--- a/packages/platform/atoms/event-types/payments/PaymentForm.tsx
+++ b/packages/platform/atoms/event-types/payments/PaymentForm.tsx
@@ -5,7 +5,7 @@ import dayjs from "@calcom/dayjs";
 import { PayIcon } from "@calcom/features/bookings/components/event-meta/PayIcon";
 import { Price } from "@calcom/features/bookings/components/event-meta/Price";
 import type { PaymentPageProps } from "@calcom/features/ee/payments/pages/payment";
-import { APP_NAME, WEBSITE_URL } from "@calcom/lib/constants";
+import { APP_NAME, WEBSITE_URL, CURRENT_TIMEZONE } from "@calcom/lib/constants";
 import getPaymentAppData from "@calcom/lib/getPaymentAppData";
 import { useLocale } from "@calcom/lib/hooks/useLocale";
 import { isBrowserLocale24h } from "@calcom/lib/timeFormat";
@@ -40,8 +40,7 @@ export const PaymentForm = ({
   const eventName = paymentInfo?.booking.title;
 
   const is24h = isBrowserLocale24h();
-  const timezone =
-    localStorage.getItem("timeOption.preferredTimeZone") || dayjs.tz.guess() || "Europe/London";
+  const timezone = localStorage.getItem("timeOption.preferredTimeZone") || CURRENT_TIMEZONE;
   const date = dayjs.utc(paymentInfo?.booking.startTime).tz(timezone);
 
   if (isLoading) return <h1 className="p-4 pt-4 text-xl">Loading...</h1>;