How it works

isithot.today answers one question: will today feel hot where you are? Here is how we get from a pile of forecasts to a single Yes, Almost or No.

Several forecasts, one answer

Weather services run their own computer models, and they rarely agree to the degree. We ask 8 of them for today's high: ECMWF, GFS, ICON, UKMO, Météo-France, MET Norway, GEM and JMA. Some models do not cover every place, so we use whichever ones answer.

With five or more forecasts we drop the single highest and lowest, then average the rest. That keeps one wild forecast from dragging the answer around. We do the same for the "feels like" temperature, which accounts for humidity and wind.

How much the forecasts agree

Under the answer you will see something like "5 of 6 forecasts agree within 2 °". Each dot on the strip is one forecast; the shaded band covers 2° either side of the blended high. When most dots sit inside the band, you can trust the answer. When they are scattered, the weather is genuinely uncertain, and it is worth checking a detailed forecast.

Hot for where you are

24°C feels hot in Newcastle and mild in Seville. So we compare today's feels-like high with the long-term climate where you are: how warm your coldest and warmest months normally get. Half of the verdict comes from that local comparison and half from the temperature itself, because people feel both. A few common-sense limits apply: below 18°C it is never "hot", and above 25°C it is never "cold".

The "warmer than usual" line compares today's high with the normal high for this date. Normals come from NASA's long-term records on a grid about 50 km across, so they describe the regional average; coasts, hills and city centres can run a degree or two either side.

Your location

We start with an approximate location from your internet connection. If you allow it, your device location is used instead, rounded to about 5 km before it leaves your browser. You can also search for any place. Read more in our privacy notice.

Where the data comes from

• Forecasts: Open-Meteo.com , licensed under CC BY 4.0 .
• Climate normals: NASA POWER (Prediction Of Worldwide Energy Resources), long-term monthly averages of daily highs.
• Place names: GeoNames , licensed under CC BY 4.0.

Forecasts are estimates. For anything that matters, like heat health warnings, check your national weather service.