I just implemented a simple weather page for the Gemini community:
gemini://tilde.cafe/~stack/weather
By default the geographic location for the forecast is based on your IP address. If you want to see a forecast for a different location, just type it in at the end of the URL, after a '?'. For example,
gemini://tilde.cafe/~stack/weather?nyc
You can also see some Moon-related info with
gemini://tilde.cafe/~stack/weather?Moon
This is a simple CGI front for wttr.in.
Enjoy.