diff --git a/docs/expiration_warnings.md b/docs/expiration_warnings.md
index 671ecdf..6bbeefc 100644
--- a/docs/expiration_warnings.md
+++ b/docs/expiration_warnings.md
@@ -6,7 +6,6 @@ By annotating a key with an expiration date, `dotenv-diff` can:
 
 - warn when a key is expired
 - warn when a key is close to expiration
-- fail the process in `--strict` mode
 
 ## Syntax
 
@@ -40,29 +39,21 @@ TOKEN_D=...
 - The annotation applies to the **next env key only**
 - If no key follows, no warning is created
 
-## Warning output
+## Behavior
 
-When expiration annotations are found, CLI output includes an `Expiration warnings` section.
+`dotenv-diff` uses two expiration thresholds:
 
-Severity is shown from `daysLeft`:
-
-- `< 0`: expired (`EXPIRED ... days ago`)
-- `0`: `EXPIRES TODAY`
-- `1`: `expires tomorrow`
-- `2-3`: urgent warning
-- `4-7`: warning
-- `> 7`: still shown as informational warning
+- `<= 7 days`: treated as error and returns exit code `1`
+- `<= 20 days`: treated as warning (error in strict mode)
 
 ## Strict mode
 
-In strict mode, expiration warnings are treated as blocking warnings and return exit code `1`.
+In strict mode, expiration warnings at `<= 20 days` are treated as blocking warnings and return exit code `1`.
 
 ```bash
 dotenv-diff --strict
 ```
 
-If expiration warnings exist, strict mode includes them in the strict error summary.
-
 ## Enable / disable
 
 Expiration warnings are enabled by default.
diff --git a/packages/cli/src/config/constants.ts b/packages/cli/src/config/constants.ts
index 00e4418..e5b164a 100644
--- a/packages/cli/src/config/constants.ts
+++ b/packages/cli/src/config/constants.ts
@@ -65,12 +65,15 @@ export const ALLOWED_CATEGORIES = [
   'gitignore',
 ] as const;
 
-/** * Threshold in days for showing expiration warnings for environment variables.
- * Variables expiring within this number of days or already expired will trigger a warning.
+/**
+ * Threshold in days for showing expiration warnings for environment variables.
+ * Expiration warnings are shown for variables with expiration dates within this threshold.
+ * Expiration warnings do not trigger an error exit by default, but can be promoted to errors with strict mode.
  */
 export const EXPIRE_THRESHOLD_DAYS = 20;
 
-/** Threshold in days for showing urgent expiration warnings.
- * Variables expiring within this number of days or already expired will trigger a high-severity warning.
+/**
+ * Threshold in days for urgent expiration checks.
+ * Expiration warnings at or below this value trigger an error exit even without strict mode.
  */
 export const URGENT_EXPIRE_DAYS = 7;
diff --git a/packages/cli/src/services/detectEnvExpirations.ts b/packages/cli/src/services/detectEnvExpirations.ts
index e159106..f98626d 100644
--- a/packages/cli/src/services/detectEnvExpirations.ts
+++ b/packages/cli/src/services/detectEnvExpirations.ts
@@ -1,6 +1,9 @@
 import fs from 'fs';
 import type { ExpireWarning } from '../config/types.js';
 
+// Number of milliseconds in a day
+const MS_PER_DAY = 1000 * 60 * 60 * 24;
+
 /**
  * Detects expiration warnings in a dotenv file.
  * fx:
@@ -27,7 +30,7 @@ export function detectEnvExpirations(filePath: string): ExpireWarning[] {
     const expireMatch = line.match(reg);
 
     if (expireMatch) {
-      pendingExpire = expireMatch[2]!; // capture dato
+      pendingExpire = expireMatch[2]!; // capture date
       continue;
     }
 
@@ -37,10 +40,12 @@ export function detectEnvExpirations(filePath: string): ExpireWarning[] {
       const key = line.split('=')[0];
 
       if (key && pendingExpire) {
-        const expireDate = new Date(pendingExpire);
-        const now = new Date();
-        const diffMs = expireDate.getTime() - now.getTime();
-        const diffDays = Math.ceil(diffMs / (1000 * 60 * 60 * 24));
+        const diffDays = calculateDaysLeft(pendingExpire, new Date());
+
+        if (diffDays === null) {
+          pendingExpire = null;
+          continue;
+        }
 
         warnings.push({
           key,
@@ -55,3 +60,27 @@ export function detectEnvExpirations(filePath: string): ExpireWarning[] {
 
   return warnings;
 }
+
+/**
+ * Calculates remaining days from today (UTC day) to a YYYY-MM-DD expiration date.
+ * Using UTC day boundaries avoids timezone and time-of-day drift.
+ * @param expireDateStr - Expiration date in YYYY-MM-DD format
+ * @param now - Current date
+ * @returns Number of days left until expiration, or null if invalid date
+ */
+function calculateDaysLeft(expireDateStr: string, now: Date): number | null {
+  const parts = expireDateStr.split('-').map(Number);
+  if (parts.length !== 3) return null;
+
+  const [year, month, day] = parts;
+  if (!year || !month || !day) return null;
+
+  const expireUtc = Date.UTC(year, month - 1, day);
+  const todayUtc = Date.UTC(
+    now.getUTCFullYear(),
+    now.getUTCMonth(),
+    now.getUTCDate(),
+  );
+
+  return Math.ceil((expireUtc - todayUtc) / MS_PER_DAY);
+}
diff --git a/packages/cli/test/unit/services/detectEnvExpirations.test.ts b/packages/cli/test/unit/services/detectEnvExpirations.test.ts
index 33c4ae8..06b7d90 100644
--- a/packages/cli/test/unit/services/detectEnvExpirations.test.ts
+++ b/packages/cli/test/unit/services/detectEnvExpirations.test.ts
@@ -125,4 +125,26 @@ describe('detectEnvExpirations', () => {
       { key: 'B', date: '2024-12-20', daysLeft: 19 },
     ]);
   });
+
+  it('is stable across time-of-day for the same calendar date', () => {
+    vi.setSystemTime(new Date('2024-12-01T23:59:59.000Z'));
+
+    fs.writeFileSync(
+      envPath,
+      `
+      # @expire 2024-12-31
+      API_KEY=123
+      `,
+    );
+
+    const result = detectEnvExpirations(envPath);
+
+    expect(result).toEqual([
+      {
+        key: 'API_KEY',
+        date: '2024-12-31',
+        daysLeft: 30,
+      },
+    ]);
+  });
 });