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
An average high-temperature of a still tropical 88.2°F (31.2°C) marks September, exhibiting a close resemblance to the conditions in August. Upland's September nights cool down significantly from the day's heat, to an average low-temperature of 63.5°F (17.5°C).Heat index
The heat index for September is calculated to be a hot 89.6°F (32°C). Staying active during long-term exposure might result in a state of exhaustion and cause heat cramps.The metrics for the heat index are tailored for both shady environments and light winds. The heat index has the possibility to be enhanced by 15 Fahrenheit (8 Celsius) degrees when there is direct sun exposure.
Note: The heat index, also known as 'feels like' or 'felt air temperature', is an aggregate value of air's warmth and moisture to show the human-felt temperature. Factors such as metabolic variation, pregnancy, and physical activity play a role in one's impression of weather. 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 particularly important for children. Kids are usually more vulnerable than adults, given their lesser sweating ability. Along with their larger skin surface relative to their small stature and the excess heat due to their activity, their risk is amplified.
Humidity
In September, the average relative humidity is 44%.Rainfall
In Upland, during September, the rain falls for 2.5 days and regularly aggregates up to 0.12" (3mm) of precipitation. Throughout the year, there are 49.6 rainfall days, and 7.8" (198mm) of precipitation is accumulated.Snowfall
In Upland, California, snow does not fall in January, March through December.Daylight
In Upland, the average length of the day in September is 12h and 22min.On the first day of the month, sunrise is at 6:24 am and sunset at 7:15 pm. On the last day of September, sunrise is at 6:44 am and sunset at 6:35 pm PDT.
Sunshine
The average sunshine in September is 10.7h.UV index
In Upland, the average daily maximum UV index in September is 6. A UV Index value of 6 to 7 symbolizes a high health hazard from unsafe exposure to UV radiation for the average person.Note: In September, a daily maximum UV index of 6 leads to the following instructions:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. Stay out of direct sunlight between 10 a.m. and 4 p.m., when UV radiation is most intense, and remember that not all shade structures provide complete protection. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is it hot during September?
What is the average humidity in September?
How many days does it rain in September in Upland?
When it does not snow?
What is the average length of the day in September?
When are sunrise and sunset in September?
How many hours of sunshine does Upland have in September?
What is the UV index reading in September?
Average temperature in September
Upland, CA
- Average high temperature in September: 88.2°F
The warmest month (with the highest average high temperature) is August (91°F).
The month with the lowest average high temperature is December (62.1°F).
- Average low temperature in September: 63.5°F
The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is December (45.5°F).
Average pressure in September
Upland, CA
- Average pressure in September: 29.88"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).
Average wind speed in September
Upland, CA
- Average wind speed in September: 4.4mph
The windiest months (with the highest average wind speed) are April and May (5.8mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).
Average humidity in September
Upland, CA
- Average humidity in September: 44%
The months with the highest relative humidity are March and May (54%).
The month with the lowest relative humidity is August (42%).
Average rainfall in September
Upland, CA
- Average rainfall in September: 0.12"
The wettest month (with the highest rainfall) is February (1.77").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in September
Upland, CA
- Average rainfall days in September: 2.5 days
The month with the highest number of rainy days is March (7.1 days).
The month with the least rainy days is June (1.2 days).
Average snowfall days in September
Upland, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).
Average daylight in September /
Average sunshine in September
Upland, 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 4min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 54min).
Average sunshine days in September
Upland, CA
- Average sunshine days in September: 25.4 days
The month with the most sunshine days is June (28.2 days).
The month with the least sunshine days is February (21.5 days).
Average UV index in September
Upland, CA
- Average UV index in September: 6
The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).
Average cloud cover in September
Upland, CA
- Average cloud cover in September: 6
The month with the most cloud cover is December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in September
Upland, 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).
Upland, California, USA
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