Rates a round of golf or a trip to the range. GoDay scores every daylight hour and finds the best 4-hour stretch of each day, about the length of 18 holes.
Also on the page, but not in the score: wind direction.
Lightning is the big one: a storm holds the score at 1, and one due within two hours at 3. Rain over 3 mm an hour holds it at 3, and more than 40 mm in the last day (a waterlogged course) at 4.
Daylight counts too: at dusk the score is held at 3, and once it's dark at 1.
Under 20 km/h (12 mph) hardly moves the ball. From 20 to 35 km/h (12 to 22 mph) you'll be clubbing up, and past 50 km/h (31 mph) GoDay rates it a gale.
GoDay looks at the last 24 hours of rain: under 5 mm the course is likely firm, up to 15 mm soft, and past 30 mm wet. Check with your club for closures.
Any thunderstorm in the forecast drops the score to 1. A golf course is one of the most exposed places to be in a storm, so GoDay treats it as a no-go.