Barcelona isn’t often cold, as it experiences a Mediterranean climate which offers warm yet dry summer months and humid winter months. On an average, the temperature usually experienced in this city during the day is 20 degrees Celsius and at night you are looking at 11 degree Celsius temperature. January is the coldest month, which sees temperatures that range from 8 to 17 degrees Celsius.If you are looking for the best time to visit Barcelona, April or September are good months. The reason for this is that the city is a little quieter around this time, but the weather is still nice and sunny (usually) which makes for a pleasant vacation. If you want to avoid all the hustle and bustle of this busy city, it is better to go when it is quieter. In general, these are the best months in Barcelona, weather permitting.