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 snowfall 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
The dawn of September sees an average high-temperature of a warm 85.3°F (29.6°C), subtly contrasting with August's 87.1°F (30.6°C). During September, Irwindale notes a substantial drop from the daytime peak to an average minimum temperature of 63.5°F (17.5°C).Heat index
The heat index for September is evaluated at a hot 86°F (30°C). Prolonged exposure and physical activity might induce exhaustion, potentially causing heat cramps.Regarding the heat index, one should be aware it's determined by shaded settings and mild winds. Direct sunlight might lead to a heat index increase by up to 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. One's perception of temperature is subjective, varying based on their activity and individual heat perception, influenced by factors like wind, clothing, and metabolic variations. It is essential to realize that direct sunlight can escalate the perceived temperature, increasing the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly important for children. Youngsters typically face more danger than adults since they sweat less. Their larger skin surface compared to their small bodies and heightened heat production from their activities augment their vulnerability.
Humidity
In Irwindale, the average relative humidity in September is 49%.Rainfall
In Irwindale, during September, the rain falls for 2.8 days and regularly aggregates up to 0.12" (3mm) of precipitation. Throughout the year, in Irwindale, there are 49.6 rainfall days, and 8.11" (206mm) of precipitation is accumulated.Snowfall
January through November are months without snowfall.Daylight
In September, the average length of the day is 12h and 22min.On the first day of September in Irwindale, sunrise is at 6:25 am and sunset at 7:17 pm. On the last day of the month, sunrise is at 6:46 am and sunset at 6:36 pm PDT.
Sunshine
In September, the average sunshine is 10.8h.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 unsafe exposure to UV radiation for the average person.Note: The maximum UV index, 6 during September, leads to the following recommendations:
Prevent overexposure. Protection from the sun's harmful effects is needed. Avoid direct exposure to the Sun between 10 a.m. and 4 p.m., the peak period for UV radiation, noting that objects like parasols or canopies might not offer complete sun protection. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot does it get in Irwindale in September?
What is the average humidity in September in Irwindale?
How many days does it rain in September in Irwindale?
When it does not snow in Irwindale?
What is the average length of the day in September in Irwindale?
When are sunrise and sunset in September in Irwindale?
How many hours of sunshine does Irwindale have in September?
When is the highest UV index in Irwindale?
What is the UV index reading in September in Irwindale?
Average temperature in September
Irwindale, CA
- Average high temperature in September: 85.3°F
The warmest month (with the highest average high temperature) is August (87.1°F).
The month with the lowest average high temperature is December (63.1°F).
- Average low temperature in September: 63.5°F
The month with the highest average low temperature is August (64.9°F).
The coldest months (with the lowest average low temperature) are February and December (47.3°F).
Average pressure in September
Irwindale, CA
- Average pressure in September: 29.89"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in September
Irwindale, CA
- Average wind speed in September: 4.4mph
The windiest months (with the highest average wind speed) are April and May (5.7mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).
Average humidity in September
Irwindale, CA
- Average humidity in September: 49%
The months with the highest relative humidity are May and June (57%).
The month with the lowest relative humidity is November (46%).
Average rainfall in September
Irwindale, CA
- Average rainfall in September: 0.12"
The wettest month (with the highest rainfall) is February (1.73").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in September
Irwindale, CA
- Average rainfall days in September: 2.8 days
The month with the highest number of rainy days is March (6.5 days).
The month with the least rainy days is June (1.2 days).
Average snowfall days in September
Irwindale, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (0.1 days).
The months with the least snowfall days are January, February, March, April, May, June, July, August, September, October and November (0 days).
Average daylight in September /
Average sunshine in September
Irwindale, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in September: 10h and 5min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are January, February and December (Average sunshine: 6h and 54min).
Average sunshine days in September
Irwindale, CA
- Average sunshine days in September: 25.9 days
The month with the most sunshine days is June (28.3 days).
The month with the least sunshine days is February (21.5 days).
Average UV index in September
Irwindale, 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, March, November and December (UV index 4).
Average cloud cover in September
Irwindale, CA
- Average cloud cover in September: 7
The months with the most cloud cover are March and December (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in September
Irwindale, 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).
Irwindale, California, USA
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