September weather forecast
San Luis, Guatemala

The first month of the autumn, September, is also a hot month in San Luis, Guatemala, with temperature in the range of an average high of 30.5°C (86.9°F) and an average low of 20.7°C (69.3°F).

Temperature

Welcoming September, San Luis notes an average high-temperature of a still tropical 30.5°C (86.9°F), nearly consistent with August's 31.5°C (88.7°F). Throughout September nights, San Luis experiences a consistent temperature average of 20.7°C (69.3°F).

Heat index

The heat index value for September is calculated to be a blistering 41°C (105.8°F). Undertake extra safety actions, heat cramps and heat exhaustion are expected. Heatstroke may result from lengthy activity.
The heat index's values are generally associated with conditions in shade and light breezes. Direct sunlight has the potential to heighten heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is a calculation that merges air temperature and relative humidity to depict the sensation of warmth. An individual's temperature experience can be influenced by extra factors, including metabolic differences, activity levels, and clothing. When in direct sunlight, one should be cautious as it can raise the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Children usually face more risks than adults as their ability to sweat is less. Additionally, their larger skin surface in relation to their petite bodies and higher heat output due to their activities increases their vulnerability.
The innate cooling system of the human body revolves around perspiration, with the evaporation of sweat being central to this process. In the presence of high relative humidity, the evaporation rate diminishes, resulting in the body retaining more warmth compared to dry conditions. When the body's heat gain surpasses its removal capacity, body temperature starts to climb, leading to potential heat-related ailments.

Humidity

In September, the average relative humidity in San Luis is 85%.

Rainfall

In San Luis, in September, during 27.9 rainfall days, 156mm (6.14") of precipitation is typically accumulated. Throughout the year, in San Luis, there are 260.2 rainfall days, and 1135mm (44.69") of precipitation is accumulated.

Daylight

In San Luis, Guatemala, the average length of the day in September is 12h and 13min.
On the first day of the month, sunrise is at 05:44 and sunset at 18:10. On the last day of September, sunrise is at 05:47 and sunset at 17:47 CST.

Sunshine

In San Luis, the average sunshine in September is 7h.

UV index

The average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health risk from unprotected exposure to Sun's UV rays for the ordinary person.
Note: In September, the maximum UV index of 6 suggests these recommendations:
Shield from overexposure. Defense against sun-related harm is required. The Sun's UV radiation is at its strongest between the hours of 10 a.m. and 4 p.m. Minimize direct exposure to the sun during this period. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.