Weather in San Isidro in January

A good month. January works. It is not the peak, but nothing about it fights you. Highs average 26.4 °C, lows 20.1 °C, and rain falls on 13 days — nothing in the month is working against you.

January ranks 2 of 12 in San Isidro. Only February scores clearly higher, and the difference is small enough to be settled by price rather than weather.

Rain on 13 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. 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 January reaches 30 °C. Across the twenty years measured, the hottest January day reached 29.8 °C and the coldest night fell to 16.2 °C, and the wettest single day dropped 50 mm — roughly 50% of the month's rain in one day.

January is moderately variable: 20 mm in the driest year against 348 mm in the wettest, around an average of 101 mm. Roughly two Januarys 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 81%, high enough to notice on the warm days without dominating them.

How January sits in the year

Temperatures hold steady either side: 26.1 °C in December, 26.4 here, 27.8 in February. Nothing about the timing within the month matters much. Rain has already shifted: 6 days fewer than December had.

Daylight in January

San Isidro sits close enough to the equator that daylight barely moves all year — 11.6 hours in January, 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

Peak season. Expect the highest prices of the year and to be booking well ahead. If the dates are flexible, March is the trade worth considering — 10 points weaker on weather, and materially quieter.

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

January 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 January — 2 °C cooler, 4 days less rain. Limón is the weaker option in January — within a degree on temperature, 4 days more rain.

So: January is effectively as good as it gets here — 2 points behind February, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in San Isidro

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