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.
Averages for Cancun in March. Weather lowdown. The weather slowly begins to heat up even further in this part of Mexico during March, when the average temperature jumps to 25Â°C, accompanied by afternoon highs of up to 30Â°C and lows of 22Â°C.