[joshvm]

Lots of reasons why you might want more local though. My local airport is more than 10km away (but there are other monitoring stations). Pilots and controllers assume some uncertainty because even within the airport perimeter there will be temperature and wind variation, but they will be in-calibration which is the main advantage. Controllers often rely on pilots to make reports if conditions differ to what the airport is recording, so it's not always considered the absolute truth.

At home, for example: more accurate irrigation control based on local rainfall, greenhouse control, microclimate variations (which can be significant if you live in a hilly or mountainous region), observatory control for astronomers etc. There are lots of reasons why your local conditions could vary considerably from the airport, but you do need to put some effort into enclosures to avoid biases from solar radiation. You can also add other sensors like buried temperature sensors to monitor the soil, cloud cover, etc.

Microclimate is significant. If you live in a city, you'll likely have urban heating effects. If you live up a hill, you will have significantly different measurements to an airport in a valley. Anyone who's been hiking knows that you absolutely need local observations to assess conditions (eg from a hut). Though this is more for illustration, if you're hiking there are normally special weather services for common routes (Austria has a nice site for this I think).

The Met Office runs an API where you can contribute your own measurements [1]. Sites are rated based on quality of instrumentation - note that the gold standard here could be a calibrated mercury thermometer in a Stephenson screen, nothing special. Calibration is key.

These simple weather stations can also be used indoors as cheap multi room thermometers. You can pair them with air quality, gas and particulate sensors. Also a nice exercise in mesh/multi sensor networking.

[1] https://wow.metoffice.gov.uk/

[RNCTX]

Yes, I should have qualified that the airport API thing is much more practical in the US, I suppose, since we spend more on aviation than other countries.

Our government since WW2 has subsidized any city which wants an airport so they can have one.

I just took a look at the Dallas, Texas airspace as an example and there are 14 weather stations within the ring defining the metro area's restricted airspace. It looks like the airspace around London-Heathrow has 3.

[joshvm]

Here you'd probably want to use local automatic weather stations (AWS), which are a superset that includes major airports. There are lot more of those around London than just Heathrow. I imagine NOAA has a similar setup.

https://www.metoffice.gov.uk/research/climate/maps-and-data/...

I'm not sure if the CAA and Met Office share stations though. Airports often have more specific instruments like ceilometers to give measurements of cloud layer height, while AWS might have more cliamtologic things like pyranometers for sunlight hours.

[billfor]

I live in the US and use my local weatherstation to control my basement dehumidifier and decide whether or not to turn the thermostats. The airport is about 10miles away but actually doesn't have all of the data that I need, such as soil temp, leaf moisture, and it's not very local to my specific house which has lots of trees and tends to deviate from the airport that is more exposed. I still use the airport data, but integrated with my own local data to get a better picture of what's going on.