San Miguel de Allende is in central Mexico -- prepare for extremes! The weather can be very hot during the day, but much, much cooler at night. 40°F/25°C swings are not uncommon, with drops to freezing on occasion in Dec/Jan.  Bring a light jacket to put on over your short sleeves.

San Miguel is a year-round destination with over 320 days of sunshine. It is generally dry and dusty in springtime, the hottest month being May when daytime temperatures can rise to 90°F/35°C. Rainy season: June - October. However, rain usually comes in short bursts and it's rare for there to be days of consistent cloud. Plus it's greener in summer.

For the current forcast: http://www.weather.com/outlook/travel...  

Click here for historical climate information