diff --git a/.changeset/floppy-cobras-stick.md b/.changeset/floppy-cobras-stick.md
new file mode 100644
index 00000000000..2cde69b188a
--- /dev/null
+++ b/.changeset/floppy-cobras-stick.md
@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Fix Cron.next and Cron.sequence around timezone boundaries
diff --git a/packages/effect/src/internal/dateTime.ts b/packages/effect/src/internal/dateTime.ts
index 544ecd86efa..e63f033819d 100644
--- a/packages/effect/src/internal/dateTime.ts
+++ b/packages/effect/src/internal/dateTime.ts
@@ -256,8 +256,12 @@ export const unsafeMakeZoned = (input: DateTime.DateTime.Input, options?: {
   }
   let zone: DateTime.TimeZone
   if (options?.timeZone === undefined) {
-    const offset = new Date(self.epochMillis).getTimezoneOffset() * -60 * 1000
-    zone = zoneMakeOffset(offset)
+    const zoneName = Intl.DateTimeFormat().resolvedOptions().timeZone
+    const parsedZone = zoneFromString(zoneName)
+    if (Option.isNone(parsedZone)) {
+      throw new IllegalArgumentException(`Invalid time zone: ${zoneName}`)
+    }
+    zone = parsedZone.value
   } else if (isTimeZone(options?.timeZone)) {
     zone = options.timeZone
   } else if (typeof options?.timeZone === "number") {
diff --git a/packages/effect/test/Cron.test.ts b/packages/effect/test/Cron.test.ts
index 0452ea792b3..c34acdcbf33 100644
--- a/packages/effect/test/Cron.test.ts
+++ b/packages/effect/test/Cron.test.ts
@@ -173,6 +173,10 @@ describe("Cron", () => {
     deepStrictEqual(next().pipe(DateTime.formatIsoZoned), b.pipe(DateTime.formatIsoZoned))
     deepStrictEqual(next().pipe(DateTime.formatIsoZoned), c.pipe(DateTime.formatIsoZoned))
     deepStrictEqual(next().pipe(DateTime.formatIsoZoned), d.pipe(DateTime.formatIsoZoned))
+
+    const seq = Cron.sequence(Cron.unsafeParse("5 2 * * 6"), new Date("2020-11-01 0:00:01Z"))
+    deepStrictEqual(seq.next().value, new Date("2020-11-07T07:05:00.000Z"))
+    deepStrictEqual(seq.next().value, new Date("2020-11-14T07:05:00.000Z"))
   })
 
   it("handles transition out of daylight savings time", () => {