Weather in San Isidro in April

Shoulder season. April sits in between. You will get good days and you will lose some. You should expect rain on 17 days of the month, which is more days wet than dry.

April ranks 7 of 12 in San Isidro: past the worst of the year but short of February, which is the month to book if the dates are open.

Rain on 17 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 29.2 °C days and 21.1 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 9 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest April day reached 32.3 °C and the coldest night fell to 17.7 °C, and the wettest single day dropped 58 mm — roughly 46% of the month's rain in one day.

April is moderately variable: 52 mm in the driest year against 254 mm in the wettest, around an average of 125 mm. Roughly two Aprils in three land near that average, and the third does something else entirely.

Wind is light at 1.6 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 78%, high enough to notice on the warm days without dominating them.

How April sits in the year

Temperatures hold steady either side: 29.2 °C in March, 29.2 here, 27.5 in May. Nothing about the timing within the month matters much. Rain is the thing that moves: May brings 9 days more of it, so the earlier half of a flexible trip is the safer half.

Daylight in April

San Isidro sits close enough to the equator that daylight barely moves all year — 12.3 hours in April, against a range of just 1.1 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: 9.3 °C between the year's warmest afternoons and coldest nights. At 713 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.

April in San Isidro versus nearby

If San Isidro is one option among several, the nearby comparison is worth making. San José is a better bet in April — within a degree on temperature, 4 days less rain. Limón is close enough to be a coin toss — within a degree on temperature, 2 days more rain.

So: April works, with February the better month by 17 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in San Isidro

See all twelve months in San Isidro, or where else to go in April.