There are many people who use Windy who have outdoor thermometers but don't have a way to get those observations online for various reasons. I was thinking that it could be cool to have a spot for registered users to manually enter temperature observations to be added to the map when current temperatures are selected on the display for 30 minutes or so after the report is made. This could be done using a simple form in the app or website and using the device's current location to get the location for the report.
It could also be made so that observations made by the same user within 5 km and 30 minutes of a previous one would just update that one (that way there aren't a bunch in the same place), while observations outside that 5 km would show a new one on the map. An example of this could be if I made an observation at home and then down the street a few minutes later, the latter would replace the former on the map, but if I made an observation at home and then another outside of town, they would both show as different reports for 30 minutes after the report is made.
Obviously some people would submit false reports for various reasons. With the other data on Windy, other users should be able to easily recognize these. If someone is making false reports routinely, they could be blocked from accessing this feature.