gpg --keyserver keyserver.ubuntu.com --recv-key B3A4FFCCC3EA7977
gpg -a --export B3A4FFCCC3EA7977 | sudo apt-key add -

echo "deb https://deb.evilbunny.org stable main" | sudo tee /etc/apt/sources.list.d/weewxapp.list > /dev/null

sudo apt-get update
sudo apt-get install weewxapp