Rates a game of tennis on an outdoor court, and works for pickleball and padel too. Wind decides it more than anything, because it moves the ball. Then comes rain, which makes a court slippery and closes grass and clay, then the heat. GoDay scores each hour and finds the best 2-hour window of each day.
Also on the page, but not in the score: wind direction.
Any drizzle holds the score at 5, and rain over 0.3 mm an hour at 3, because the court will be wet. A thunderstorm holds it at 1, and one due within two hours at 3. Wind over 35 km/h (22 mph) holds it at 3, and a feels-like above 38°C (100°F) at 3.
Daylight counts too: once it's dark the score is held at 5.
Under 8 km/h (5 mph) is calm. By 15 km/h (9 mph) you'll notice it on high balls, past 22 km/h (14 mph) it moves the ball a lot, and over 35 km/h (22 mph) GoDay holds the score at 3.
Hard courts dry quickly, but GoDay only knows the forecast, not your court. Drizzle holds the score at 5, and rain over 0.3 mm an hour at 3. Grass and clay courts often close after rain, so check with your club.
Yes. Both are played outdoors and both mind the wind, pickleball most of all because of its light plastic ball, so read the wind card closely. Indoor courts don't need a forecast.