diff --git a/packages/core/src/intl.context.ts b/packages/core/src/intl.context.ts
index dd01357..12a1149 100644
--- a/packages/core/src/intl.context.ts
+++ b/packages/core/src/intl.context.ts
@@ -7,6 +7,7 @@ import { type IntlMessage } from './types/intl-message';
 export type IntlContextValue = {
   message?: IntlMessage;
   locale: string;
+  now?: Date;
   timeZone?: string;
   formats?: Partial<Format>;
   onError: (error: IntlError) => void;
diff --git a/packages/core/src/intl.provider.tsx b/packages/core/src/intl.provider.tsx
index 6bd26f3..e73aa14 100644
--- a/packages/core/src/intl.provider.tsx
+++ b/packages/core/src/intl.provider.tsx
@@ -12,7 +12,7 @@ function defaultGetMessageFallback({ key, namespace }: DefaultGetMessageFallback
 }
 
 type IntlProviderProps = React.PropsWithChildren<
-  Pick<IntlContextValue, 'message' | 'locale' | 'formats' | 'timeZone'> &
+  Pick<IntlContextValue, 'message' | 'locale' | 'formats' | 'now' | 'timeZone'> &
     Partial<Pick<IntlContextValue, 'onError' | 'getMessageFallback'>>
 >;
 
diff --git a/packages/core/src/use-intl.ts b/packages/core/src/use-intl.ts
index 2037dde..21df63a 100644
--- a/packages/core/src/use-intl.ts
+++ b/packages/core/src/use-intl.ts
@@ -41,7 +41,7 @@ function getRelativeTimeFormatConfig(seconds: number) {
 }
 
 export function useIntl() {
-  const { formats, locale, timeZone, onError } = useIntlContext();
+  const { formats, locale, now: globalNow, timeZone, onError } = useIntlContext();
 
   function resolveFormatOrOptions<Format>(
     typeFormats: Record<string, Format> | undefined,
@@ -120,14 +120,26 @@ export function useIntl() {
     });
   }
 
-  function formatRelativeTime(date: number | Date, now: number | Date) {
-    const dateDate = date instanceof Date ? date : new Date(date);
-    const nowDate = now instanceof Date ? now : new Date(now);
+  function formatRelativeTime(date: number | Date, now?: number | Date) {
+    try {
+      if (now == null) {
+        if (globalNow != null) {
+          now = globalNow;
+        } else {
+          throw new Error(
+            process.env.NODE_ENV !== 'production'
+              ? `The \`now\` parameter wasn't provided to \`formatRelativeTime\` and there was no global fallback configured on the provider.`
+              : undefined,
+          );
+        }
+      }
 
-    const seconds = (dateDate.getTime() - nowDate.getTime()) / 1_000;
-    const { unit, value } = getRelativeTimeFormatConfig(seconds);
+      const dateDate = date instanceof Date ? date : new Date(date);
+      const nowDate = now instanceof Date ? now : new Date(now);
+
+      const seconds = (dateDate.getTime() - nowDate.getTime()) / 1_000;
+      const { unit, value } = getRelativeTimeFormatConfig(seconds);
 
-    try {
       return new Intl.RelativeTimeFormat(locale, { numeric: 'auto' }).format(value, unit);
     } catch (_error) {
       const error = _error as SystemError;
diff --git a/packages/core/src/use-now.ts b/packages/core/src/use-now.ts
new file mode 100644
index 0000000..824cfba
--- /dev/null
+++ b/packages/core/src/use-now.ts
@@ -0,0 +1,30 @@
+import React from 'react';
+
+import { useIntlContext } from './intl.provider';
+
+type UseNowOptions = {
+  updateInterval?: number;
+};
+
+export function useNow(options?: UseNowOptions) {
+  const updateInterval = options?.updateInterval;
+
+  const { now: globalNow } = useIntlContext();
+  const [now, setNow] = React.useState(globalNow || new Date());
+
+  React.useEffect(() => {
+    if (Boolean(updateInterval) === false) {
+      return undefined;
+    }
+
+    const intervalId = setInterval(() => {
+      setNow(new Date());
+    }, updateInterval);
+
+    return () => {
+      clearInterval(intervalId);
+    };
+  }, [updateInterval]);
+
+  return now;
+}
diff --git a/packages/core/test/use-intl.test.tsx b/packages/core/test/use-intl.test.tsx
index bc2be80..8b37c14 100644
--- a/packages/core/test/use-intl.test.tsx
+++ b/packages/core/test/use-intl.test.tsx
@@ -19,7 +19,7 @@ describe('formatDateTime', () => {
     }
 
     render(
-      <IntlProvider message={{}} locale="en">
+      <IntlProvider locale="en">
         <Component />
       </IntlProvider>,
     );
@@ -91,7 +91,7 @@ describe('formatDateTime', () => {
       }
 
       render(
-        <IntlProvider timeZone="Asia/Seoul" message={{}} locale={'en'}>
+        <IntlProvider timeZone="Asia/Seoul" locale={'en'}>
           <Component />
         </IntlProvider>,
       );
@@ -114,7 +114,7 @@ describe('formatDateTime', () => {
       }
 
       render(
-        <IntlProvider timeZone="Asia/Seoul" message={{}} locale={'en'}>
+        <IntlProvider timeZone="Asia/Seoul" locale={'en'}>
           <Component />
         </IntlProvider>,
       );
@@ -123,6 +123,22 @@ describe('formatDateTime', () => {
     });
   });
 
+  it('can use a global `now` fallback', () => {
+    function Component() {
+      const intl = useIntl();
+      const mockDate = new Date('1984-11-20T10:36:00.000Z');
+      return <>{intl.formatRelativeTime(mockDate)}</>;
+    }
+
+    render(
+      <IntlProvider now={new Date('2018-11-20T10:36:00.000Z')} locale={'en'}>
+        <Component />
+      </IntlProvider>,
+    );
+
+    screen.getByText('34 years ago');
+  });
+
   describe('error handling', () => {
     it('handles missing formats', () => {
       const onError = vi.fn();
@@ -133,7 +149,7 @@ describe('formatDateTime', () => {
       }
 
       const { container } = render(
-        <IntlProvider onError={onError} message={{}} locale={'en'}>
+        <IntlProvider onError={onError} locale={'en'}>
           <Component />
         </IntlProvider>,
       );
@@ -155,7 +171,7 @@ describe('formatDateTime', () => {
       }
 
       const { container } = render(
-        <IntlProvider onError={onError} message={{}} locale={'en'}>
+        <IntlProvider onError={onError} locale={'en'}>
           <Component />
         </IntlProvider>,
       );
@@ -167,6 +183,28 @@ describe('formatDateTime', () => {
       );
       expect(container.textContent).toMatch(/Oct 01 2023/);
     });
+
+    it('throws when no `now` value is available', () => {
+      const onError = vi.fn();
+
+      function Component() {
+        const intl = useIntl();
+        const mockDate = new Date('1984-11-20T10:36:00.000Z');
+        return <>{intl.formatRelativeTime(mockDate)}</>;
+      }
+
+      render(
+        <IntlProvider onError={onError} locale={'en'}>
+          <Component />
+        </IntlProvider>,
+      );
+
+      const error: IntlError = onError.mock.calls[0][0];
+      expect(error.code).toBe(IntlErrorCode.FORMATTING_ERROR);
+      expect(error.message).toBe(
+        "FORMATTING_ERROR: The `now` parameter wasn't provided to `formatRelativeTime` and there was no global fallback configured on the provider.",
+      );
+    });
   });
 });
 
@@ -178,7 +216,7 @@ describe('formatNumber', () => {
     }
 
     render(
-      <IntlProvider message={{}} locale="en">
+      <IntlProvider locale="en">
         <Component />
       </IntlProvider>,
     );
@@ -225,7 +263,7 @@ describe('formatNumber', () => {
       }
 
       const { container } = render(
-        <IntlProvider onError={onError} message={{}} locale={'en'}>
+        <IntlProvider onError={onError} locale={'en'}>
           <Component />
         </IntlProvider>,
       );
@@ -247,7 +285,7 @@ describe('formatNumber', () => {
       }
 
       const { container } = render(
-        <IntlProvider onError={onError} message={{}} locale={'en'}>
+        <IntlProvider onError={onError} locale={'en'}>
           <Component />
         </IntlProvider>,
       );
@@ -268,7 +306,7 @@ describe('formatRelativeTime', () => {
     }
 
     render(
-      <IntlProvider message={{}} locale="en">
+      <IntlProvider locale="en">
         <Component />
       </IntlProvider>,
     );
@@ -332,7 +370,7 @@ describe('formatRelativeTime', () => {
       }
 
       const { container } = render(
-        <IntlProvider onError={onError} message={{}} locale={'en'}>
+        <IntlProvider onError={onError} locale={'en'}>
           <Component />
         </IntlProvider>,
       );
diff --git a/packages/core/test/use-now.test.tsx b/packages/core/test/use-now.test.tsx
new file mode 100644
index 0000000..6220e0d
--- /dev/null
+++ b/packages/core/test/use-now.test.tsx
@@ -0,0 +1,72 @@
+import { render, waitFor } from '@testing-library/react';
+import { expect, it } from 'vitest';
+
+import { IntlProvider } from '../src/intl.provider';
+import { useNow } from '../src/use-now';
+
+it('returns the current time', () => {
+  function Component() {
+    return <p>{useNow().toISOString()}</p>;
+  }
+
+  const { container } = render(
+    <IntlProvider locale="en">
+      <Component />
+    </IntlProvider>,
+  );
+  expect(container.textContent).toMatch(/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.\d{3}Z$/);
+});
+
+it('can use a globally defined `now` value', () => {
+  function Component() {
+    return <p>{useNow().toISOString()}</p>;
+  }
+
+  const { container } = render(
+    <IntlProvider locale="en" now={new Date('2018-10-06T10:36:01.516Z')}>
+      <Component />
+    </IntlProvider>,
+  );
+  expect(container.textContent).toBe('2018-10-06T10:36:01.516Z');
+});
+
+it('can update a globally defined `now` value after the initial render', async () => {
+  function Component() {
+    return <p>{useNow({ updateInterval: 100 }).toISOString()}</p>;
+  }
+
+  const { container } = render(
+    <IntlProvider locale="en" now={new Date('2018-10-06T10:36:01.516Z')}>
+      <Component />
+    </IntlProvider>,
+  );
+  expect(container.textContent).toBe('2018-10-06T10:36:01.516Z');
+
+  await waitFor(() => {
+    if (!container.textContent) throw new Error();
+    const curYear = parseInt(container.textContent);
+
+    expect(curYear).toBeGreaterThan(2020);
+  });
+});
+
+it('can update based on an interval', async () => {
+  function Component() {
+    return <p>{useNow({ updateInterval: 100 }).toISOString()}</p>;
+  }
+
+  const { container } = render(
+    <IntlProvider locale="en">
+      <Component />
+    </IntlProvider>,
+  );
+  if (!container.textContent) throw new Error();
+  const initial = new Date(container.textContent).getTime();
+
+  await waitFor(() => {
+    if (!container.textContent) throw new Error();
+    const now = new Date(container.textContent).getTime();
+    expect(now - 900).toBeGreaterThanOrEqual(initial);
+    expect(4).toBeGreaterThanOrEqual(3);
+  });
+});