Effects of high humidity. Humidity is considered too high when its level goes above 45% - 50%, sometimes as high as 80% and up. High humidity can be especially dangerous when combined with high temperature - as mentioned above, high humidity disrupts the body's ability to cool itself, which may lead to a heat stroke.
The average sea surface temperature in April 2017 for Cancun was 84.0Â°F. The maximum and minimum values were 83.0Â°F and 85.4Â°F respectively.
January and February are the coolest months; June and July are the hottest. Cancun Weather. Even though the temperature does not vary that much throughout the year, there are 2 distinct seasons in Cancun. The wet (rainy) season is May to October and it is slightly hotter. Cancun's dry season is November to April. It is much cooler also. The best time of year to travel to Cancun (weather-wise) is during the dry season's coolest months: January and February. March and April are the driest months of the year, and also the sunniest months in Cancun. Humidity is high in Cancun, often around 80%. April and May have the lowest humidity.