Or buy a complete weather station which includes an anemometer. I have this one and it works well (although not for measuring light rainfall): https://shop.ecow

Or buy a complete weather station which includes an anemometer. I have this one and it works well (although not for measuring light rainfall): https://shop.ecowitt.com/en-gb/products/wittboy https://shop.ecowitt.com/en-gb/products/wittboy Less fun because nothing can be build, although the transmitted data conforms to standards and can be processed with for example https://github.com/merbanan/rtl_433 https://github.com/merbanan/rtl_433. So one can gather all data with a simple dongle and process that with a RPi.