Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
La Mesa records an average high-temperature of a still warm 81.5°F (27.5°C) in September, closely mirroring the climate of the previous month. La Mesa encounters an average low-temperature of 64.4°F (18°C) during September nights.Heat index
The heat index value for September is appraised at 84.2°F (29°C). If one sustains activity during exposure, it could lead to a sense of fatigue, with a chance of heat cramps.It is worth noting that heat index values are gauged for conditions in the shade and light breezes. Being under direct sunlight might amplify the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'real feel', determines the feeling of heat when you account for the relative humidity. The perception of temperature can be subjective, varying based on activity and individual heat sensitivity, influenced by factors like wind, attire, and metabolic variations. Keep in mind that direct sunshine exposure can amplify the weather's effects, possibly increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Youngsters often neglect the necessity for rest and hydration. Thirst is a sign of advancing dehydration - thus the importance of maintaining hydration, specifically during long-lasting physical activities.
Humidity
In La Mesa, the average relative humidity in September is 61%.Rainfall
In La Mesa, California, in September, it is raining for 3.7 days, with typically 0.28" (7mm) of accumulated precipitation. Throughout the year, there are 54.5 rainfall days, and 6.57" (167mm) of precipitation is accumulated.Daylight
In La Mesa, the average length of the day in September is 12h and 22min.On the first day of September, sunrise is at 6:23 am and sunset at 7:12 pm. On the last day of the month, sunrise is at 6:42 am and sunset at 6:33 pm PDT.
Sunshine
In La Mesa, the average sunshine in September is 10.3h.UV index
June through September, with an average maximum UV index of 6, are months with the highest UV index. A UV Index of 6 to 7 symbolizes a high health vulnerability from exposure to the Sun's UV radiation for average individuals.Note: In September, a daily maximum UV index of 6 leads to the following instructions:
Avoid excessive sunlight. Those with lighter skin may experience burning in less than 20 minutes. Avoid direct sunlight between the hours of 10 a.m. and 4 p.m., when UV radiation is at its peak. Keep in mind that shade structures may not provide complete protection. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
What is the average humidity in September?
How many days does it rain in September?
How many hours of daylight does La Mesa have in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
What is the month with the highest UV index?
What is the UV index intensity in September?
Average temperature in September
La Mesa, CA
- Average high temperature in September: 81.5°F
The warmest month (with the highest average high temperature) is August (82.6°F).
The month with the lowest average high temperature is December (64.2°F).
- Average low temperature in September: 64.4°F
The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is February (48.7°F).
Average pressure in September
La Mesa, CA
- Average pressure in September: 29.88"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).
Average wind speed in September
La Mesa, CA
- Average wind speed in September: 4.7mph
The windiest month (with the highest average wind speed) is April (5.7mph).
The calmest month (with the lowest average wind speed) is October (4.5mph).
Average humidity in September
La Mesa, CA
- Average humidity in September: 61%
The month with the highest relative humidity is May (68%).
The month with the lowest relative humidity is November (55%).
Average rainfall in September
La Mesa, CA
- Average rainfall in September: 0.28"
The wettest month (with the highest rainfall) is February (1.3").
The driest month (with the least rainfall) is June (0.08").
Average rainfall days in September
La Mesa, CA
- Average rainfall days in September: 3.7 days
The month with the highest number of rainy days is March (7.8 days).
The month with the least rainy days is June (1.4 days).
Average daylight in September /
Average sunshine in September
La Mesa, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in September: 10h and 2min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 6h and 42min).
Average sunshine days in September
La Mesa, CA
- Average sunshine days in September: 24.6 days
The month with the most sunshine days is June (28.1 days).
The month with the least sunshine days is February (21 days).
Average UV index in September
La Mesa, CA
- Average UV index in September: 6
The months with the highest UV index are June, July, August and September (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 4).
Average cloud cover in September
La Mesa, CA
- Average cloud cover in September: 11
The month with the most cloud cover is March (Cloud cover 24).
The month with the least cloud cover is August (Cloud cover 8).
Average visibility in September
La Mesa, CA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
La Mesa, California, USA
Weather forecast for your location
2. Allow the app to use your location