The weather app for the court
Knowday reads the wind, the glare, and whether the court dried out from overnight rain — then tells you when today is good to play.
Today · your court
What matters on the court
Is the court actually dry?
A court that soaked overnight plays slick under a clear sky. Knowday watches the last day's rain *and* the rain window — so "sunny" doesn't mean "playable" by mistake.
Wind on the ball
A tennis lob or a pickleball dink lives or dies on a calm court. Knowday reads the wind and finds the steadiest window.
Glare on the serve
A hard, cloudless sky throws glare on serves and lobs — a little cloud is kinder. Knowday reads cloud cover so the light isn't fighting you.
Heat you'll feel on asphalt
The feels-like for the run, plus the honest note that a dark court runs hotter than the air. Hydrate accordingly.
How it works
It scores the feels-like, wind, the rain window and downpour rate, recent rain for a dry-court read, humidity, glare from the sky, and UV.
One honest limit: it reads the air, not the court surface — dark asphalt runs hotter than the temperature shown, so treat a borderline-hot day as hotter underfoot.
Court sports is one of fourteen plans Knowday reads — walks and rides, the lawn, the garden, camping, the night sky, and the water.
See all plansNo catch
Free to use. No sign-up. Your location is only used to fetch your forecast.