Hello,
Try this:
1) "Uninstall app updates" for the Weather app, in phone's settings
2) Install this zip in your custom recovery (TWRP/OrangeFox/etc.) then reboot your device:
TWRP_MIUI_Weather_Xiaomi.eu_G-12.3.6.16_Installation.zip
3) Clear "All app data" of the Weather app, in phone's settings
Open the Weather app and check if it works well.