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: Weather Forecast. The warmest day over the next 7 days in Cancun is forecast to be 23rd April at 30Â°C (86Â°F) and the warmest night on 21st April at 24Â°C (75Â°F). The average temperature over the next 7 days is forecast to be 29Â°C (84Â°F) and there will be 5 days of sunshine . The average for April is 26Â°C (79Â°F) in Cancun.