Cool, looks like a nice DIY project. It doesn’t mention how to collect rain data though (except a link to a rain sensor product page). The ability to collect rain data would make it a more complete weather station.
A while back I wrote a few blog posts about reverse engineering a number of off-the-shelf wireless sensors (temp/humidity/rain/soil moisture): https://rayshobby.net/wordpress/reverse-engineer-wireless-temperature-humidity-rain-sensors-part-1/
and my original goal was to leverage these cheap wireless sensors to collect weather data locally. Other than having a bunch of fun, these didn’t make to the firmware, largely because the encoding method of almost every sensor is unique so it’s very difficult to accommodate all wireless sensors on the market.