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.
Cancun, a resort town in southern Mexico, sees its hottest weather in July or August, when average temperatures reach 90 to 92 degrees. The evenings cool off a bit, with temperatures falling to between 76 and 80 degrees. The coolest month in Cancun is January, when average highs range from 80 to 82 degrees and lows average 66 to 68 degrees.