Het weer in Tamarindo, Costa Rica in september

San Juan del Sur's forum describes September and October as the heaviest rain of the year here, but the typical day still follows a manageable rhythm: cooler and overcast at dawn, clouds burning off by mid-morning, then sunny through the afternoon before rain returns. Posters said showers roll in roughly every other day and usually last only an hour or two rather than the whole day. A few forum regulars specifically preferred August over September, since the risk of a genuinely wet stretch climbs the closer you get to the end of the month.

Tamarindo's forum consistently rates July as one of the better rainy-season months - genuinely the driest stretch of the wet season here, with sunny mornings, clouding over by early afternoon, and a shower or thunderstorm that clears out again rather than lingering. Locals reportedly call this the 'little summer of San Juan,' a real break within the rainy season that feels more like a dry-season week. Daytime temperatures stay in the high 80s F, and forum regulars were clear this counts as a genuinely good month to visit, not a compromise pick.

Forum posters describe January as dry and beautiful, squarely inside Guanacaste's dry season - daytime highs commonly in the low 30sC with bright sun essentially every day, evenings cooling to a comfortable high-20sC. The landscape stays green early in the dry season, though posters note the strong 'December winds' (part of the broader Papagayo/Guanacaste wind pattern) can already be drying things out fast. Beaches generally aren't too windy through most of January, though the very start of the month - the wet-to-dry season transition - can see a stronger, gustier stretch. Overall, posters consistently rate January among the most reliable months here for classic sunny beach weather.