Weather in San Luis Potosí in May

A good month. May works. It is not the peak, but nothing about it fights you. Highs average 30.6 °C, lows 14.2 °C, and rain falls on 7 days — nothing in the month is working against you.

May ranks 9 of 12 in San Luis Potosí: past the worst of the year but short of December, which is the month to book if the dates are open.

Rain on 7 days, 1 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 30.6 °C days and 14.2 °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: 20 days top 30 °C, making the heat continuous rather than occasional; the day swings 16.3 °C from low to high, which means one bag has to cover both. Across the twenty years measured, the hottest May day reached 37 °C and the coldest night fell to 6.8 °C.

May is moderately variable: 3 mm in the driest year against 83 mm in the wettest, around an average of 28 mm. Roughly two Mays in three land near that average, and the third does something else entirely.

Wind is light at 10.6 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 49%.

How May sits in the year

Temperatures hold steady either side: 29.8 °C in April, 30.6 here, 28.7 in June. Nothing about the timing within the month matters much. Rain is the thing that moves: June brings 7 days more of it, so the earlier half of a flexible trip is the safer half.

Daylight in May

May is at or near the longest days of San Luis Potosí's year: 13.2 hours of daylight, gaining 0.4 hours across the month. Evenings are the real gain — dinner outdoors still happens in full light.

An inland climate

Despite being inland, the year stays fairly even: 24.5 °C between the year's warmest afternoons and coldest nights. At 1886 m, altitude is doing as much work here as latitude: thinner air means fierce sun by day and heat that leaves the moment it sets. Within May itself the daily swing is 16.3 °C, so mornings and afternoons need different clothes.

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 Luis Potosí versus nearby

If San Luis Potosí is one option among several, the nearby comparison is worth making. Santiago de Querétaro is close enough to be a coin toss — within a degree on temperature, 2 days more rain. Morelia is close enough to be a coin toss — within a degree on temperature, 2 days more rain.

So: May is a compromise. December is 27 points better and is what San Luis Potosí 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 Luis Potosí

See all twelve months in San Luis Potosí, or where else to go in May.