The chance of rain where you are standing, as one button with the number in it. Your telephone knows where it is; the sky over that spot has been forecast already. This page puts the two together and hands you the only number that decides anything outdoors. Tap the button and it checks again. Whether 62% means you go anyway is still yours — the tool is called what you say when you don't: taking a rain check.

Blue is rain. The button fills from the floor up like a gauge, exactly as far as the chance; past fifty the number itself turns blue, because from there on rain is the likelier world. Under the button stands how many millimetres that would be.

Three windows. The hour you are in, the next three, or everything that is left of today — the number is the worst hour in the window, because one wet hour is all it takes.

What leaves your telephone: one place, nothing else. Your position is rounded to about a hundred metres and sent to Open-Meteo, an open weather service, which answers with the forecast for that spot. No account, no key, no cookie; nothing is stored here or there, and the page writes nothing to any server of ours.