Weather in Cancún

August is the warmest month (average 28.6°C, high 30.5°C) and January is the coolest (average 24.2°C, low 22.0°C). That 4.4°C swing in monthly averages is the first thing to plan around in Cancún.

Rain is the monsoon runs from August to November, inside an annual total of 1250 mm. The wettest month is October at 224 mm; the driest is March at 38 mm. Cancún is in Mexico at 21.2°N. The 2001–2020 NASA POWER daily record describes a monsoon climate with a sharp wet-dry split. On this site the months that score closest to a 22°C day, lighter rain, and moderate humidity are January, March, and April.

How warm Cancún gets

The heat peaks in August, when the typical afternoon is 30.5°C. The opposite pole is January, when mornings average 22.0°C.

Across the year the mean afternoon high is 28.8°C. If you want the smallest day–night shock, look at months where the high and low sit close together; August nights still hold 26.7°C.

When Cancún gets wet

The monsoon in Cancún starts in August and ends in November (August, September, October, and November). October is the core of it at 224 mm. March is the other extreme, with 38 mm.

Humidity peaks near 82%. That usually lines up with the wetter months rather than the hottest ones.

The calendar in Cancún

The year bottoms out in January. Plan for 22.0°C at night and 26.4°C in the afternoon. March is the driest month, averaging only 38 mm across 6 rainy days. Highs sit near 28.2°C. May brings 92 mm and 12 rainy days; temperatures run from 25.5°C to 30.4°C. In June, Cancún averages 29.7°C by day and 26.2°C at night, with 181 mm of rain. July: 30.1°C high, 26.4°C low, 89 mm rain, 81% humidity.

August is when the monsoon typically starts in Cancún: highs near 30.5°C, and rainfall jumps to 114 mm (21 rainy days). September brings 166 mm and 24 rainy days; temperatures run from 26.5°C to 30.0°C. October is the wettest month — 224 mm and 21 rainy days, with 82% humidity. November closes the monsoon: 124 mm over 13 rainy days, then the calendar dries. December brings 68 mm and 11 rainy days; temperatures run from 23.0°C to 26.9°C.

When the score favours a visit

The three months with the highest comfort score are January, March, and April: January (24.2°C average, 63 mm, 76% humidity); March (25.6°C average, 38 mm, 73% humidity); April (26.9°C average, 41 mm, 73% humidity). They fall in calendar order. The score rewards averages near 22°C, lower rainfall, and humidity near 60%. It is a climate score, not a festival or price calendar.

If you want the monsoon itself — fewer crowds, greener landscape, heavier rain — aim at August–November instead of the score.

Cancún and other cities in Mexico

Mérida is about 289 km away: Cancún is 1.5°C cooler than Mérida in its hottest month and 204 mm wetter over the year than Mérida. Mérida’s wettest month is September (188 mm) versus October here.

Puebla is about 1209 km away: Cancún is 7.8°C warmer than Puebla in its hottest month and 372 mm wetter over the year than Puebla. Puebla’s wettest month is September (169 mm) versus October here.

Iztapalapa is about 1290 km away: Cancún is 10.9°C warmer than Iztapalapa in its hottest month and 354 mm wetter over the year than Iztapalapa. Iztapalapa’s wettest month is September (171 mm) versus October here.