September marks the beginning of the rainy season in Cancun, Cozumel, and the Mexican Caribbean. Occuring later in the year than many other Caribbean islands, the rainy season in characterized by a slight decrease in temperature and frequent late afternoon downpours.
Typical Weather in September
Temperatures in Cancun and the Mexican Caribbean during September generally vary between an average high during the day of 89.0 degrees and an average low at night of 76.0 degrees
| Monthly Averages | | High | Low | Rainfall
(inches) | No. of Days
with Rain |
| 89.0° F |
76.0° F |
N.A. |
7.0 |
|
During the early morning hours of an average September day in Cancun and the Mexican Caribbean, you can expect the temperature will be in the vicinity of 75.8 degrees.
The temperature will rise over the course of the typical September day, reaching somewhere around 87.7 degrees by early afternoon.
By the early evening hours in September the temperature will generally fall to somewhere in the vicinity of 81.9 degrees.
Overall, temperatures in Cancun and the Mexican Caribbean during September average around 82.7 degrees.
| Early Morning | Late Morning | Early Afternoon | Late Afternoon | Early Evening | Overall |
| 75.8° F |
84.6° F |
87.7° F |
86.2° F |
81.9° F |
82.7° F |
|
Rain
During September, rain is most likely to occur around 3:00 PM, and least likely to occur around 9:00 PM.
To the extent thunderstorms occur in Cancun and the Mexican Caribbean during September, they are most likely to occur around 6:00 AM, as shown in the following table.
| Percent Frequencies of Hourly Observations | | Hour | Rain
and/or
Drizzle | Thunder-
storms |
| 12:00 AM (midnight) |
2.5 % |
0 % |
| 3:00 AM |
# |
# |
| 6:00 AM |
2.1 % |
0.4 % |
| 9:00 AM |
3.5 % |
0.2 % |
| 12:00 PM (noon) |
3.6 % |
0.2 % |
| 3:00 PM |
4.8 % |
0.2 % |
| 6:00 PM |
3.7 % |
0 % |
| 9:00 PM |
1.9 % |
0 % |
| ALL |
3.4 % |
0.2 % |
|
