This program is structured on three parts:

1. Fetching cities (gountries)
2. Computing their weather with coordinates (openweathermap)
3. Saving the data into an excel file (excelize)

Don't forget to add dependencies:

go get github.com/pariz/gountries
go get github.com/briandowns/openweathermap
go get github.com/360EntSecGroup-Skylar/excelize 

Optional(for wiki_parser.go):

go get github.com/PuerkitoBio/goquery

You can run the program by typing this command:

go run main.go

I also wrote an article explaining the program. You can find it here: https://medium.com/ensias-it/tracking-the-weather-in-major-moroccan-cities-with-go-4907ffdc9c34