Weather in Cancun in August

How August compares

August is the 1st warmest month of the year in Cancun and ranks 41st of 134 destinations we compare for August - see where else is hot in August. Within Mexico it is 5th of 5 (Mexico in August). Against London's average high of 21.4°C in August, Cancun is 8.5°C warmer by day and 12.8°C warmer at night.

Daytime and night-time in August

The typical August day in Cancun peaks at 29.9°C, but that is an average: the warmest 10% of days reach 31.1°C or more. About 100% of days top 25°C and 1 in 2 pass 30°C. Nights average 26.3°C; one night in ten drops to 25.2°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest August day here reached 32.8°C (2019-08-30) and the coldest night 23.6°C (2019-08-29).

Rain in August

Wet (more than 8 rainy days): about 21 days with 1 mm or more, 146 mm in total. Year to year it varies a lot - the wettest August was 2013 with 263 mm, the driest 2018 with 54 mm. Humidity averages 81%, which makes the heat feel heavier than the thermometer suggests.

Sea temperature in August

The sea averages 28.8°C - warm enough to swim (22°c+). Depending on the year it ranges from 28.3°C to 29.3°C. For the warmest sea here, come in September (28.9°C).

Sunshine and daylight

Around 5.8 hours of sunshine a day (estimated from cloud cover), 12.7 hours of daylight: the sun rises about 06:26 and sets about 19:18 local time in mid-August. Average cloud cover is 54%.

Is August a good time to visit Cancun?

It is a reasonable choice: hot days but expect showers. The best months for Cancun on our scoring are April, March, February; months averaging 25°C or more: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.

Hot days and little relief after dark

August is Cancun's warmest month, and the heat is persistent rather than occasional. Half of days reach 30°C, while humidity averages 81%, so allow for a sticky feel rather than judging comfort by the temperature alone. Put more active outdoor plans earlier in the day and keep midday flexible for shade or an indoor break. Loose, breathable clothes make sense, and air conditioning is a sensible accommodation priority if warm bedrooms disturb your sleep. Evenings are warm enough for light clothing, but they are not a reliable chance to cool off. This is a better fit for heat lovers than travellers who prefer mild conditions.

Expect rain to affect your plans

With about 21 rainy days, August is a wet choice, so rain needs to be part of your planning rather than treated as an unlikely interruption. That does not mean every rainy day is a washout: there is still about 5.8 hours of sunshine a day on average. However, those figures do not promise a dependable dry spell at any particular time. Keep weather-sensitive plans movable, carry a light waterproof and have an indoor alternative you would genuinely enjoy. If your main aim is to spend each day outside without checking the weather, the rain is a substantial drawback, even with the warmth.

Warm sea, with sunshine to work around

The sea averages 29°C, making swimming a strong reason to consider August if you dislike a chilly first dip. It is close to the average daytime air temperature, though, so do not expect the water to feel especially cool. There are about 12.7 hours of daylight, giving you room to move outdoor time around changing weather rather than sticking to a rigid schedule. Pack swimwear alongside sun protection and rain cover: neither the wet monthly outlook nor the heat tells the whole story. August works best for travellers happy to mix swimming and outdoor time with breaks, rather than those seeking uninterrupted sun.