Weather in San José in August

A good month. August is a solid month to be in San José. You should expect rain on 24 days of the month, which is more days wet than dry.

August ranks 9 of 12 in San José: past the worst of the year but short of February, which is the month to book if the dates are open.

Rain on 24 of the month's 31 days, 6 of them heavy. At that frequency a wet-weather backup is not a contingency, it is the itinerary — book the indoor things first and treat the clear days as the bonus. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: it never really gets hot: not one day in an average August reaches 30 °C. Across the twenty years measured, the hottest August day reached 28 °C and the coldest night fell to 14.7 °C, and the wettest single day dropped 99 mm — roughly 50% of the month's rain in one day.

August is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest August on record still delivered 373 mm against 87 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 198 mm average is a reasonable planning figure, not a promise.

Wind is light at 1.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 88%, high enough to notice on the warm days without dominating them.

How August sits in the year

Temperatures hold steady either side: 23.9 °C in July, 23.9 here, 23.3 in September. Nothing about the timing within the month matters much.

Daylight in August

San José sits close enough to the equator that daylight barely moves all year — 12.5 hours in August, against a range of just 1.2 hours across the whole calendar. Sunrise and sunset land at roughly the same time whenever you come.

An inland climate

Despite being inland, the year stays fairly even: 12 °C between the year's warmest afternoons and coldest nights. At 1133 m the air is thin enough to matter — sun that burns faster than the temperature suggests, and nights that cool off quickly.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

August in San José versus nearby

If San José is one option among several, the nearby comparison is worth making. San Isidro is close enough to be a coin toss — 2.6 °C warmer, 2 days more rain. Puntarenas is the weaker option in August — 6.9 °C warmer, 1 day less rain.

So: August is a compromise. February is 24 points better and is what San José is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in San José

See all twelve months in San José, or where else to go in August.