Live · Live radar where available (minutes old); forecast model elsewhere
Rain
Where a national weather service shares its radar, you see rain measured minutes ago, with a two-hour replay. Everywhere else the layer shows how much rain the forecast model expects, in millimetres per hour.
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How weather radar works
A radar dish sends out short pulses of microwaves and listens for the echo. Raindrops, snowflakes and hail reflect part of the pulse back. The stronger the echo, the heavier the rain; the time the echo takes to return gives the distance. Turning the dish all the way round builds a map of rain within a few hundred kilometres.
What dBZ means
Radar strength is measured in dBZ, a logarithmic scale: every extra 10 dBZ means the echo is ten times stronger. As a rough guide, about 20 dBZ is light rain, about 40 dBZ heavy rain, and above about 55 dBZ often torrential rain or hail.
Measured or forecast
Radar measures rain that is falling now. The forecast model predicts rain that has not happened yet. The two can disagree, especially for short, local thunderstorms, which are hard to forecast exactly.
What the toggles show
- Rain colours (eye button)
- Shows or hides the rain shading so you can see the map underneath while keeping the timeline.
Did you know?
The United States' weather radar network, NEXRAD, has about 160 radars. Each can detect rain up to about 460 km away and measure winds inside storms within about 230 km, so together they cover almost the whole country.