The Best Time to Visit San Juan
Between mid-December and June is the best time to visit San Juan. This is the high season, so lodging will be more expensive and there will be larger crowds throughout the popular destinations in the city, but the temperature is extremely comfortable and there's the most to do in the city during these months. As the season wanes on toward April and June, lodging prices will begin to drop as crowds begin to dwindle - and these months are considered the absolute best time to visit San Juan.
Between July and September is the worst time to visit San Juan. Prices and crowds will be at their lowest, but quite a few hotels will be closed due to the upcoming hurricane season. Additionally, it will be warm and humid and you should expect rain, especially going into August.
Between October and mid-December is an excellent time to visit San Juan. The prices on hotels and airfare are down and crowds haven't begun getting too big yet. The temperature is extremely comfortable and there will be little-to-no-rain. The only downside is some restaurants and hotels may not be done getting remodeled after the extended off-season.