Wikipedia:Reference desk/Archives/Science/2025 July 22

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July 22

Weather questions

1. Why so few weather stations are located at downtowns of cities and so many are located at airports?
2. Is there any place in the US that measures sunshine hours as of 2025? The hours of US are interesting because:
   1. The sunniest place in the world, Yuma is in the US.
   2. The places in northern US with continental climates have higher winter sunshine hours than places in Europe because they are further south.

No US weatherbox that I have found has sunshine data from a period more recent than 1961-1990.

3. How common is it in Europe to use 0°C isotherm to separate group C and D climates in Köppen climate classification?
4. Are there any countries that measure dew points in weather stations?
5. Is there any European country that measures snowfall? --40bus (talk) 07:06, 22 July 2025 (UTC)[reply]

1: Accurate weather data is important for aviation safety, so weather stations at airports are normally mandatory. Downtown locations suffer from an urban heat island. The temperature they measure, and also the wind, isn't representative for a larger area. Now you might argue that for the people in the city it's nice to know what the weather in the city is like, but in a larger city of about a million people the urban heat effect downtown may be 8°C and in the suburbs only 2°C, so downtown isn't even representative for the city. If downtown has a waterfront, a tiny change in wind direction may cause a huge change in temperature. Finally, data from weather stations are fed into numerical weather forecasts. Those run at a spacial resolution of some tens of kilometres (with faster computers, this is improving), which is too coarse to resolve urban heat islands. A weather station at a ___location not representative for an area of 1000 km² will mess up the weather forecast. PiusImpavidus (talk) 08:38, 22 July 2025 (UTC)[reply]

4: Temperature and humidity are both measured at most weather stations all over the world. How humidity is measured exactly varies; see hygrometer for details. The resulting data can be converted to absolute humidity, relative humidity and dew point. Often both relative humidity and dew point are reported, but given one of them and the temperature, all can be calculated. PiusImpavidus (talk) 08:49, 22 July 2025 (UTC)[reply]

5: Norway records snow depth on a daily basis at many weather stations, see here. Mikenorton (talk) 15:45, 22 July 2025 (UTC)[reply]