How it works

Timing

There are three time spans for forecast periods: 24-hour, 6-hour, and 2-hour.

24-hour periods start at 6 AM UTC () every day. In each 24-hour period there are four 6-hour periods, and in each 6-hour period there are three 2-hour periods.

Weather

There are three severe weather types that can be forecasted:

Tornadoes

Violently rotating columns of air attached to storm clouds.

Severe Wind

Defined by the National Weather Service as gusts of at least 58 miles per hour.

Severe Hail

Defined as hail at least 1 inch in diameter (quarter sized).

Forecasting

For each weather type/time span combination, players pick a point on the map wherever they think the chosen weather type is most likely during the chosen time span. Forecasts for 24-hour time spans can be made either one or two days in advance (forecasts made two days in advance can earn bonus points). Check out the forecasting guide for some tips.

Scoring

If a forecast is close to a severe weather report of the correct weather type, the user who made the forecast will earn points. The closer/more numerous the reports are, the more points will be earned (it's like the forecast is the center of a dartboard and the weather reports are the darts - hence the name WeatherDarts). Reports are gathered from the Storm Prediction Center's storm report database. Click here for more information about storm reports and scoring.