diff --git a/packages/@aws-cdk-testing/framework-integ/test/aws-secretsmanager/test/integ.lambda-rotation.js.snapshot/tree.json b/packages/@aws-cdk-testing/framework-integ/test/aws-secretsmanager/test/integ.lambda-rotation.js.snapshot/tree.json
index 207294c8edffe..d20587d644344 100644
--- a/packages/@aws-cdk-testing/framework-integ/test/aws-secretsmanager/test/integ.lambda-rotation.js.snapshot/tree.json
+++ b/packages/@aws-cdk-testing/framework-integ/test/aws-secretsmanager/test/integ.lambda-rotation.js.snapshot/tree.json
@@ -180,7 +180,7 @@
                           ]
                         },
                         "rotationRules": {
-                          "automaticallyAfterDays": 30
+                          "scheduleExpression": "rate(4 hours)"
                         },
                         "secretId": {
                           "Ref": "SecretA720EF05"
diff --git a/packages/aws-cdk-lib/aws-secretsmanager/lib/rotation-schedule.ts b/packages/aws-cdk-lib/aws-secretsmanager/lib/rotation-schedule.ts
index 176aef993f552..ea2c432a2728a 100644
--- a/packages/aws-cdk-lib/aws-secretsmanager/lib/rotation-schedule.ts
+++ b/packages/aws-cdk-lib/aws-secretsmanager/lib/rotation-schedule.ts
@@ -131,14 +131,15 @@ export class RotationSchedule extends Resource {
     let automaticallyAfterDays: number | undefined;
     let scheduleExpression: string | undefined;
     if (props.automaticallyAfter) {
-      if (props.automaticallyAfter.toMilliseconds() > 0) {
-        if (props.automaticallyAfter.toMilliseconds() < Duration.hours(4).toMilliseconds()) {
+      const automaticallyAfterMillis = props.automaticallyAfter.toMilliseconds();
+      if (automaticallyAfterMillis > 0) {
+        if (automaticallyAfterMillis < Duration.hours(4).toMilliseconds()) {
           throw new Error(`automaticallyAfter must not be smaller than 4 hours, got ${props.automaticallyAfter.toHours()} hours`);
         }
-        if (props.automaticallyAfter.toMilliseconds() > Duration.days(1000).toMilliseconds()) {
+        if (automaticallyAfterMillis > Duration.days(1000).toMilliseconds()) {
           throw new Error(`automaticallyAfter must not be greater than 1000 days, got ${props.automaticallyAfter.toDays()} days`);
         }
-        if (props.automaticallyAfter.toHours() > 23) {
+        if (props.automaticallyAfter.toHours() >= 24) {
           automaticallyAfterDays = props.automaticallyAfter.toDays();
         } else {
           scheduleExpression = Schedule.rate(props.automaticallyAfter).expressionString;