Spring (March to May) and Fall (September to November) is the best time to visit San Diego. During Spring, the City has mild weather and relatively fewer crowds at the beginning of the season. However, as soon as May strikes, tourists rush in making the hotel fares to increase. June and August are the peak months when a huge influx of visitors gets into the city, causing priced-up accommodations and long lines. Autumn witnesses lovely weather and plenty of festivals in the city. If you have a plan for September, you'll have to make the bookings at least a few weeks before the trip. Winter hits in December until February, making the weather cool and rainy. Budget travellers can grab the opportunity of reduced hotel rates during the time.