How accurate is it?

How we test

The model learns from lightning and fires of past seasons: every strike the GOES satellites saw since 2018, and every wildfire the agencies recorded as started by lightning. It was trained on 2018–2022. Then it was tested once on two later seasons it had never seen, scoring each day as it would have that day, and we counted where the lightning fires actually started.

Each day, the squares (10 km, about 6 miles across) are ranked by the model's score. The riskiest squares making up 10% of the region's area are High; the next 10% are Elevated. A square must also reach a minimum score, so quiet days don't paint every lit square High.

Fire risk goes live in a region only after its model passes every one of the go-live checks above on the unseen seasons. Until then that region shows lightning and fuel dryness only.

What it can and can't tell you

• Most High squares never see a fire. High means "look here first", not "a fire is coming".
• Some fires start outside High squares, and some lightning fires are never recorded.
• Satellite strike positions are accurate to a few miles, so a fire can start in the square next door.
• It is a chance, not a prediction. Not an official warning. Call 911 in an emergency.

Live results

After the 2027 fire season we'll add how the live map did, season by season, next to these test results.