Pool lightning stoplight · iPhone
Green means swim.
ClearToSwim tracks lightning around your pool and runs the 30-minute all-clear countdown for you. One look tells you whether the pool is open.
Coming to the App StoreWatch radius 10 miles, all-clear wait 30 minutes 10 miles quiet for 30 minutes means the pool is open
Simulation. This card is staged: the site never uses your location and shows no live data.
POOL OPEN
- Last strike
- Updates with the state shown
- Countdown
- Runs while the pool is closed
- Updated
- Just now
What the app tells you
The free app lights the red and the green, with an alert for each. The two amber states in between are part of ClearToSwim Pro.
POOL OPEN
OPEN, UNDER CAUTION
Lightning detected nearby. A storm may be approaching.
POOL CLOSED
Lightning detected in the area. Wait for the pool to reopen.
REOPENING SOON
How it works
We watch for strikes, run the clock, and post the verdict where you can see it.
We start with the standard rule
We default to 10 miles and 30 minutes. The 30-minute wait follows National Weather Service guidance; the 10-mile radius is common aquatic-facility practice, which is stricter than the general outdoor rule. With ClearToSwim Pro, both settings adjust: the radius from 1 to 35 miles, the wait from 10 to 60 minutes in 5-minute steps.
We restart the clock on every strike
One new strike inside your radius and we start the full wait over. No shortcuts, no partial credit. That is the step that slips when someone counts by hand.
We tell you when it changes
A notification when the pool closes, and another when it is clear to swim again. You are not the one who has to keep checking.
For the person who decides
Every pool has one. We give that person one place to look.
- Pool-owning families A home pool, watched by whoever happens to be outside.
- Swim coaches Practices and meets, where clearing the water costs everybody time.
- Community pools Neighborhood and HOA pools with posted rules, many swimmers, and one person answering for all of them.
- Swim instructors Small children, tight lesson schedules, and no room to guess.
- Backyard parties Nobody is on duty, so everybody assumes somebody else is watching.
What it does not do
- Coverage It does not detect every strike. No lightning detection system does, and coverage varies by region.
- Judgment It does not decide for you. It reports what it sees so you can make the call.
- Authority It does not replace a lifeguard, a weather radio, or an official warning.
- Signal It needs a data connection. No signal means no update, and the app says so rather than showing a stale verdict as if it were current.
ClearToSwim is an informational aid, not a safety guarantee. Always follow official warnings. If you see lightning or hear thunder, get out of the water and take shelter in a substantial building or a hard-topped vehicle. Wait until 30 minutes after the last thunder before returning to the water.