February, March and April would be a good time for Guadalajara weatherwise, not too hot, beautiful blooming flowers. Many North Americans go down during the winter months to get out of the dark cold days. Lots of Canadians go down to Mexico for the winter. Be aware that in March and
April you will run into lots of "spring break" college students from the US who ceate havoc and ill will with wild partying.
January and February would be a good time.

Alice