Cancun WeatherBase 

(Editor's Note: The Monthly Precipitation Totals from Weatherunderground to the right are incorrect as of August 7, 2013. For the correct totals, please visit http://www.weatherbase.com/weather/we... )

With the sun shining on average between 240 and 253 days per year, Cancun is a year-round holiday destination, although certain times of year may be more favorable than others. High season for travel falls between December and April. During these months the weather tends to be sunny, with temperatures hovering around 85ºF (30ºC) during the day and rarely dipping far below 65ºF (18ºC) at night. While this time of year offers the most pleasant weather, it is also most popular with tourists, which drives prices up, especially during the Christmas holiday season between mid-December and the beginning of January. Travelers planning trips near Christmas or Easter and Spring Break should be advised to plan well in advance and book their accommodations early.

Many resorts drop their prices immediately after Easter, so this can be an ideal time to take a more economical vacation while the weather is still bearable. The summer months bring humid, hotter temperatures pushing the 95ºF (35ºC) mark. The hurricane season falls between June and mid-October, so travelers visiting Cancun during these months should pay careful attention to the storm watch. 2005’s Hurricane Wilma caused major havoc and destruction from which Cancun is still recovering. When there is no hurricane, the cooling winds can make the hot summer weather more bearable. The rainy season falls mostly between the end of August and the middle of November, bringing afternoon downpours and occasional floods.

For those that must swim in the "ocean" (carribean sea), it is advisable to avoid the 2nd through the 4th week in April (usually the 3rd week).  For about 7 to 10 days, the thimble jelly-fish are mating near the shore.  At best, they are unsightly, at worst, they can cause an allergic reaction if you come in contact with them (which you will if you swim in the sea) and this can result in a fever.  It is best to call ahead to see if the jelly fish season has begun or is over if making last minute plans around this time.

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Below are averages for Cancun. In the opinion of someone who lives in Cancun,  www.wunderground.com has the most accurate Cancun forecasts. During rainy season the forecasts may call for showers or thunderstorms every day, but keep in mind that most rain in Cancun is heavy but brief showers that pass quickly. It is relatively rare to have full days of rain unless there is a tropical storm nearby.

Average High Temperature
    AVG   Jan.   Feb.   Mar.   Apr.   May   Jun.   Jul.   Aug.   Sep.   Oct.   Nov.   Dec.  
C 30 27 27 28 29 31 31 32 32 31 30 28 27
F 86 81 82 84 85 88 89 90 90 89 87 84 82
 
Average Low Temperature
    AVG   Jan.   Feb.   Mar.   Apr.   May   Jun.   Jul.   Aug.   Sep.   Oct.   Nov.   Dec.  
C 23 19 20 21 22 25 25 25 25 24 23 22 20
F 74 67 68 71 73 77 78 78 77 76 74 72 69
 
Average Number of Days Above 90F/32C
    Jan.   Feb.   Mar.   Apr.   May   Jun.   Jul.   Aug.   Sep.   Oct.   Nov.   Dec.  
Days --- --- 1 3 10 17 24 25 17 7 1 ---
 
Average Number of Days Above 80F/26C
    Jan.   Feb.   Mar.   Apr.   May   Jun.   Jul.   Aug.   Sep.   Oct.   Nov.   Dec.  
Days 20 21 26 29 31 30 31 31 30 30 28 23
 
Average Number of Days With Precipitation
    Jan.   Feb.   Mar.   Apr.   May   Jun.   Jul.   Aug.   Sep.   Oct.   Nov.   Dec.  
Days 5 4 3 2 4 6 4 4 7 8 5 6
 
Average Morning Relative Humidity
    Jan.   Feb.   Mar.   Apr.   May   Jun.   Jul.   Aug.   Sep.   Oct.   Nov.   Dec.  
% 86 85 85 84 83 84 84 86 85 86 86 86
 
Average Evening Relative Humidity
    Jan.   Feb.   Mar.   Apr.   May   Jun.   Jul.   Aug.   Sep.   Oct.   Nov.   Dec.  
% 75 73 72 69 71 73 70 70 75 74 75 75
 
Average Wind Speed
    Jan.   Feb.   Mar.   Apr.   May   Jun.   Jul.   Aug.   Sep.   Oct.   Nov.   Dec.  
km/h 14 16 16 16 16 16 14 14 14 14 14 14
mph 9 10 10 10 10 10 9 9 9 9 9 9