To tweet wheater add the tag #meteo and the tag of your city without spaces.
You can also use weather tag: #m1 sunny, #m2 partly sunny, #m3 cloudly, #m4 showers, #m5 t-storm, #m6 fog, #m7 snow
#meteo #LosAngeles #m1 The sun is big as I've never seen! by @meteotw