September weather forecast
Hermosillo, Mexico

September brings an end to the intense summer temperatures of Hermosillo. Although daytime temperatures can still reach a hot 35.6°C (96.1°F), nights gradually become much cooler. September's weather marks the transition from summer to fall. The city witnesses a significant drop in rainfall from August, reverting to its typically dry climate. Cooler nights and declining rainfall make September an attractive time for visitors who wish to avoid the summer high.

Temperature

September welcomes an average high-temperature of a still very hot 35.6°C (96.1°F), not much different from the preceding month. In Hermosillo, September nights witness a steady temperature drop to a warm 26.2°C (79.2°F).

Heat index

During September, the heat index is calculated to be a scorching 42°C (107.6°F). More safety actions are required, heat exhaustion and heat cramps are probable. Long-term activity may precipitate heatstroke.
Regarding the heat index, one should be aware it's determined by shaded settings and mild winds. Under direct sunshine, the heat index values might be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'apparent temperature', is an estimation of the warmth sensation when considering humidity levels. An individual's perception of weather can be affected by a variety of elements including metabolic differences, being pregnant, and their level of physical exertion. Should you be directly under the sun, anticipate a possible increase in the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are largely significant for babies and toddlers. Young children are more at risk than adults since they tend to sweat less. Moreover, their large skin surface in proportion to their small bodies and the high heat production due to their activities contribute to their vulnerability.
By perspiring, the human body can shed its excessive warmth since evaporated sweat cools it off. In high relative humidity, the body's ability to evaporate heat is diminished, resulting in a heightened feeling of warmth. When heat surpasses the body's release mechanisms, dehydration and overheating risks become pronounced.

Humidity

In Hermosillo, Mexico, the average relative humidity in September is 49%.

Rainfall

In Hermosillo, during September, the rain falls for 11.8 days and regularly aggregates up to 59mm (2.32") of precipitation. In Hermosillo, during the entire year, the rain falls for 69.5 days and collects up to 262mm (10.31") of precipitation.

Daylight

In September, the average length of the day in Hermosillo is 12h and 19min.
On the first day of September, sunrise is at 6:01 am and sunset at 6:45 pm. On the last day of the month, sunrise is at 6:16 am and sunset at 6:10 pm MST.

Sunshine

In Hermosillo, the average sunshine in September is 9.4h.

UV index

May through September, with an average maximum UV index of 8, are months with the highest UV index. A UV Index estimate of 8 to 10 represents a very high health risk from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The UV index of 8 during September leads to these advisories:
Take all necessary measures. Eyes and skin are at risk if left unprotected. Try to minimize direct Sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Also note that objects like parasols or canopies might not provide complete sun protection. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.