September weather forecastSan Blas, Mexico

Weather in September

The first month of the autumn, September, is still a tropical month in San Blas, Mexico, with temperature in the range of an average low of 23.9°C (75°F) and an average high of 32.2°C (90°F).

Temperature

A minimal variation is noted in San Blas's average high-temperature at the onset of September, reaching a still hot 32.2°C (90°F) from August's 33.2°C (91.8°F). Throughout September, the nighttime temperature averages to a warm 23.9°C (75°F).

Heat index

For September, the heat index is appraised at a life-threatening hot 45°C (113°F). Keep on guard: Heat exhaustion and heat cramps are probable. Heatstroke is a possible danger with ongoing physical activity.
Be aware that heat index ratings are designed for shaded locations and minor breezes. Heat index values have the potential to be boosted by 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'apparent temperature' or 'feels like', joins air temperature with relative humidity to produce a temperature perception for humans. Elements such as metabolic variations, pregnancy, and physical exertion can influence one's weather perception. In direct sunlight, the heat's impact can be heightened, potentially leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly relevant to children. Typically, young kids are at a higher risk than adults since they sweat less. Also, the larger skin surface in proportion to their small bodies and the heightened heat production due to their active nature adds to their vulnerability.
The human body normally cools itself by perspiration. Excessive warmth is eliminated from the body by evaporation of sweat. During conditions of high air temperature and humidity (high heat index), the body's ability to perspire is inhibited, increasing the sensation of warmth. Excessive heat gain, when not shed effectively by the body, can result in increasing body temperatures and related hazards.

Humidity

With an average relative humidity of 79%, September is the most humid month.

Rainfall

In San Blas, Mexico, in September, it is raining for 20.5 days, with typically 92mm (3.62") of accumulated precipitation. In San Blas, Mexico, during the entire year, the rain falls for 106.3 days and collects up to 439mm (17.28") of precipitation.

Sea temperature

In San Blas, the average seawater temperature in September is 30.6°C (87.1°F).
Note: The surface water temperatures above 30°C (86°F) are arguably considered as unpleasant for swimming, and any intense water activity, as the refreshing effect of water is missing.

Daylight

In San Blas, the average length of the day in September is 12h and 16min.
On the first day of September, sunrise is at 5:44 am and sunset at 6:17 pm. On the last day of the month, sunrise is at 5:52 am and sunset at 5:49 pm MST.

Sunshine

In San Blas, Mexico, the average sunshine in September is 9.9h.

UV index

May through July, September and October, with an average maximum UV index of 7, are months with the highest UV index. A UV Index estimate of 6 to 7 represents a high health risk from unprotected exposure to Sun's UV rays for average individuals.
Note: The daily high UV index of 7 during September translates into the following recommendations:
Endorse precautions and be consistent with sun safety guidelines. Preventing sunburn is paramount. Seek shade and limit direct Sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its peak, but be aware that not all shade structures provide complete sun protection. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Attention! UV radiation is ramped up when reflecting off sand and water surfaces.