Good to know
How does it decide?
It starts with how much rain actually fell, then adjusts. It holds off if a real soak is forecast soon, and leans toward watering if it has been hot and dry, since the soil loses more to the air than a bare rainfall total shows. If it is raining on you right now it says so plainly, even when the nearest gauge has not caught it. And through the dormant winter months it eases off, because established plants barely drink.
How much rain means I can skip watering?
As a guide, about 5 mm in the last 24 hours covers most established borders. Pots and seedlings dry out faster and need more, around 8 to 10 mm, and free-draining sandy soil needs more than water-holding clay. A hot, windy spell raises the bar, as more of that rain evaporates.
Where do the readings come from?
The headline is what fell: the nearest rain gauge where one is in range (Environment Agency in England, SEPA in Scotland), otherwise an Open-Meteo estimate for your spot. The forecast and soil-dryness checks come from Open-Meteo, and the live raining-now check from RainViewer radar.
Why check before watering?
Watering ground that is already wet wastes water and can harm roots. A quick check tells you whether your garden needs it today.
Does it work outside the UK?
The forecast estimate works anywhere. Measured rain gauges cover England (Environment Agency) and Scotland (SEPA); elsewhere the headline uses the estimate.