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How to make your iPhone alarm adjust for traffic

People on r/shortcuts have been hand-building this for years. Here's a version that works, and the honest list of what it can't do.

Updated November 10, 2026 · 5 min read

Short answer A Shortcuts automation can read your travel time and set an alarm before you go to bed. It can't re-check traffic while you sleep or move an alarm later, so for that you need a dedicated traffic-aware alarm app.

Build the Shortcut

Open Shortcuts → Automation → New → Time of Day, set it to around 10 PM on workdays, and choose Run Immediately.
Add Get Travel Time from your home address to work, by driving.
Add a Date action for tomorrow at your arrival time (e.g. 9:00 AM).
Use Adjust Date to subtract the travel time, then subtract your get-ready time (e.g. 45 minutes) and a buffer (e.g. 10 minutes).
Add Create Alarm (or Change Alarm on an existing one) with the resulting time.

Test it a couple of evenings while you're still awake, and check the alarm it sets.

Where the Shortcut falls short

It only knows tonight's traffic. Travel time at 10 PM says nothing about a crash at 7 AM. The night-time estimate is close to free-flow, so you still need a big buffer.
No morning re-check. Automations don't run reliably while the phone sits locked on the nightstand, and changing an alarm you're already asleep for is fragile.
It never lets you sleep in. To be safe, you'll set it early. On clear mornings that's lost sleep.
No fail-safe. If the action errors, you might wake up with no alarm at all.
Maintenance. Different arrival times on different days mean more automations.

The no-setup alternative

Wakebird does this properly: it checks predicted traffic for your arrival time the night before, re-checks live traffic before dawn, and moves a real AlarmKit alarm earlier or later within limits you set. If traffic can't be checked, it rings at the time you set. Never later.

Frequently asked questions

Can an iPhone Shortcut change my alarm based on traffic?

Yes, partly. A time-of-day automation can get travel time and create or change an alarm the evening before. It can't reliably re-check traffic in the morning or move the alarm later.

Does the iPhone have a built-in traffic alarm?

No. The Clock app's alarms are fixed. Apple Maps can show commute times and delays, but it doesn't change your alarm.