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.
The coolest period in Cancun is in January to February with temperatures averaging 73 fahrenheit. Temperatures do not drop very much below 68 fahrenheit at night. The warmest time in Cancun with temperatures in the mid-80s is around June and July.