How accurate can IP Geolocation get? (2021)

I investigated IP geolocation accuracy to figure out how large to render the "accuracy radius" for the initial geo-ip location on my weather app (https://geolocation-survey.leftium.com/)

Initially, I thought 25km might be large enough. Sometimes it is, but other times the geo-ip location is off by 800km!

So I guess a single number for "accuracy radius" isn't good enough.

- WiFi-IP-based geolocation tends to be more accurate.

- Cellular-IP-based geolocation tends to be a crapshoot.

BigData Cloud gives a confidence area for each geo-IP location that is updated daily like this: https://www.bigdatacloud.com/what-is-my-ip

I recently wrote a large article on IP geolocation and it turns out that the main source for IP geolocation is still WHOIS data: https://ipapi.is/geolocation.html