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
September's weather displays an average high-temperature of a warm 84.2°F (29°C), slightly varied from August's 87.3°F (30.7°C). Alpine records a consistent low-temperature of 62.8°F (17.1°C) during September nights.Heat index
September's average heat index is computed to be a tropical 86°F (30°C). Long-lasting exposure and activity potentially induce a sense of weariness, with the risk of heat cramps.The metrics for the heat index are tailored for both shady environments and light winds. The presence of direct sunlight can raise the heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', gives an indication of how one might feel in terms of heat after considering humidity. A person's impression of weather can be swayed by numerous aspects, among them metabolic variations, pregnancy, and activity levels. 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 extremely significant for babies and toddlers. Kids are generally in more danger than adults because they perspire less. Their large skin surface area compared to their small bodies and the excessive heat due to their actions raises their risk.
Humidity
In Alpine, California, the average relative humidity in September is 53%.Rainfall
In Alpine, in September, during 5.5 rainfall days, 0.51" (13mm) of precipitation is typically accumulated. In Alpine, during the entire year, the rain falls for 62 days and collects up to 6.38" (162mm) of precipitation.Daylight
The average length of the day in September in Alpine is 12h and 22min.On the first day of September, sunrise is at 6:22 am and sunset at 7:11 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 6:32 pm PDT.
Sunshine
In September, the average sunshine is 10.4h.UV index
The months with the highest UV index are June through September, with an average maximum UV index of 6. A UV Index reading of 6 to 7 represents a high health hazard from exposure to the Sun's UV radiation for the ordinary person.Note: In September, the UV index of 6 transforms into the following advice:
Use protective steps and abide by sun safety guidelines. Safeguarding against skin and eye harm is necessary. Stay in the shade and avoid direct Sun exposure from 10 a.m. to 4 p.m., a time when UV radiation is at its strongest, and remember that parasols or canopies do not offer full protection. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot does it get in September?
What is the average humidity in September?
How much does it rain in September?
How many hours of daylight does Alpine have in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
When is the highest UV index?
How high is the UV index in September?
Average temperature in September
Alpine, CA
- Average high temperature in September: 84.2°F
The warmest month (with the highest average high temperature) is August (87.3°F).
The month with the lowest average high temperature is December (61.3°F).
- Average low temperature in September: 62.8°F
The month with the highest average low temperature is August (64.9°F).
The coldest month (with the lowest average low temperature) is February (44.2°F).
Average pressure in September
Alpine, CA
- Average pressure in September: 29.86"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).
Average wind speed in September
Alpine, CA
- Average wind speed in September: 4.1mph
The windiest month (with the highest average wind speed) is May (5.7mph).
The calmest month (with the lowest average wind speed) is September (4.1mph).
Average humidity in September
Alpine, CA
- Average humidity in September: 53%
The month with the highest relative humidity is May (62%).
The month with the lowest relative humidity is November (51%).
Average rainfall in September
Alpine, CA
- Average rainfall in September: 0.51"
The wettest month (with the highest rainfall) is February (0.94").
The driest month (with the least rainfall) is June (0.08").
Average rainfall days in September
Alpine, CA
- Average rainfall days in September: 5.5 days
The month with the highest number of rainy days is March (7.6 days).
The month with the least rainy days is June (1.5 days).
Average daylight in September /
Average sunshine in September
Alpine, 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 months with the most sunshine are June and July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 42min).
Average sunshine days in September
Alpine, CA
- Average sunshine days in September: 21.8 days
The month with the most sunshine days is June (27.5 days).
The month with the least sunshine days is July (19.4 days).
Average UV index in September
Alpine, 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 November and December (UV index 3).
Average cloud cover in September
Alpine, CA
- Average cloud cover in September: 8
The months with the most cloud cover are March and December (Cloud cover 23).
The month with the least cloud cover is August (Cloud cover 6).
Average visibility in September
Alpine, 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).
Alpine, California, USA
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