Weather in San José in May

A good month. May 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.

May ranks 6 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, 8 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 May reaches 30 °C. Across the twenty years measured, the hottest May day reached 30.8 °C and the coldest night fell to 13.2 °C, and the wettest single day dropped 66 mm — roughly 30% of the month's rain in one day.

May is moderately variable: 90 mm in the driest year against 671 mm in the wettest, around an average of 220 mm. Roughly two Mays in three land near that average, and the third does something else entirely.

Wind is light at 2.1 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 81%, high enough to notice on the warm days without dominating them.

How May sits in the year

The month is on the way down: 2.3 °C cooler than April, with June dropping another 1.8 °C. The first week and the last are not the same trip. Rain has already shifted: 11 days more than April had.

Daylight in May

San José sits close enough to the equator that daylight barely moves all year — 12.6 hours in May, 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.

May in San José versus nearby

If San José is one option among several, the nearby comparison is worth making. San Isidro is the weaker option in May — within a degree on temperature, 2 days more rain. Puntarenas is the weaker option in May — 6.9 °C warmer, 3 days less rain.

So: May 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 May.