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
As August turns into September, the average high-temperatures rest at a still warm 83.3°F (28.5°C), showing a minor variation from the prior month. September is characterized by a distinct thermal shift, with nighttime lows averaging at a cool 54.1°F (12.3°C).Heat index
In September, the heat index is calculated to be a tropical 86°F (30°C). Fatigue might occur with continuous exposure and activity, potentially causing heat cramps.When assessing, remember that heat index measurements are for light winds and shaded spots. The heat index values could be amplified by up to 15 Fahrenheit (8 Celsius) degrees in direct sunlight.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', is an amalgamation of air temperature and humidity to express the equivalent perceived temperature. This effect is personal, influenced by the individual's physical activity and heat sensitivity, shaped by factors including wind, attire, and metabolic variations. When exposed to direct sunlight, it's possible for the heat index to increase by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Younglings frequently fail to recognize the requirement to rest and rehydrate. Thirst emerges late in dehydration - it is imperative to keep hydration levels high, particularly during extended physical exertions.
Humidity
September is the least humid month, with an average relative humidity of 57%.Rainfall
Months with rainfall are January through May, September through December. September is the first month it rains. Throughout September, in the average 1.7 rainfall days, it receives 0.04" (1mm) of precipitation. In Gilroy, during the entire year, the rain falls for 43.4 days and collects up to 3.66" (93mm) of precipitation.Daylight
The average length of the day in September is 12h and 24min.On the first day of September, sunrise is at 6:37 am and sunset at 7:34 pm. On the last day of the month, sunrise is at 7:01 am and sunset at 6:50 pm PDT.
Sunshine
The average sunshine in September is 11.3h.UV index
In September, the average daily maximum UV index is 5. A UV Index of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.Note: The maximum daily UV index of 5 in September interprets into the following recommendations:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it hot during September?
What is the least humid month?
What is the average humidity in September?
When does it start raining?
What is the average length of the day in September?
What time are sunrise and sunset in September?
How many hours of sunshine does Gilroy have in September?
What is the UV index intensity in September?
Average temperature in September
Gilroy, CA
- Average high temperature in September: 83.3°F
The warmest month (with the highest average high temperature) is August (85.1°F).
The month with the lowest average high temperature is December (57.6°F).
- Average low temperature in September: 54.1°F
The months with the highest average low temperature are August and September (54.1°F).
The coldest months (with the lowest average low temperature) are February and March (40.6°F).
Average pressure in September
Gilroy, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).
Average wind speed in September
Gilroy, CA
- Average wind speed in September: 4.2mph
The windiest month (with the highest average wind speed) is May (5.3mph).
The calmest month (with the lowest average wind speed) is November (3.9mph).
Average humidity in September
Gilroy, CA
- Average humidity in September: 57%
The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is September (57%).
Average rainfall in September
Gilroy, CA
- Average rainfall in September: 0.04"
The wettest month (with the highest rainfall) is December (0.83").
The driest months (with the least rainfall) are June, July and August (0").
Average rainfall days in September
Gilroy, CA
- Average rainfall days in September: 1.7 days
The month with the highest number of rainy days is March (8.3 days).
The month with the least rainy days is August (0.6 days).
Average daylight in September /
Average sunshine in September
Gilroy, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 42min).
- Average sunshine in September: 11h and 2min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 0min).
Average sunshine days in September
Gilroy, CA
- Average sunshine days in September: 27.7 days
The month with the most sunshine days is July (29.9 days).
The month with the least sunshine days is March (21.4 days).
Average UV index in September
Gilroy, CA
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Gilroy, CA
- Average cloud cover in September: 9
The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 7).
Average visibility in September
Gilroy, 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).
Gilroy, California, USA
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