Follow the guides and tutorials at https://github.com/raspberrypilearning/weather_station_guide (published at www.raspberrypi.org/weather-station)
This repo contains the updated version of the software, re-engineered for the Stretch version of Raspbian. If you are an existing Weather Station owner and are using a Pi running the Jessie version of Raspbian, then this code will not work without modification. You should flash your SD card with the latest Raspbian image and perform a fresh install of this software (you may wish to take a copy of your local MYSQL database first).