Run meson to configure the build environment and then ninja to build
meson build --prefix=/usr
cd build
ninja
To install, use ninja install
sudo ninja install
Download prebuild binairy from Release
Install it by coping file to wingpanel plugin folder as below.
sudo cp libweather.so /usr/lib/x86_64-linux-gnu/wingpanel/libweather.so
pkill -9 wingpanel
Get secret key from openweathermap.org and store it in your config file.
cat ~/.weather.config
{
"key":"XXXXXXXXXXXXXXXXXXXX"
}