September weather forecastSouth Pasadena, CA
September
Weather in September
September, the first month of the autumn in South Pasadena, is still a warm month, with temperature in the range of an average high of 84.4°F (29.1°C) and an average low of 63.7°F (17.6°C).Temperature
South Pasadena observes an average high-temperature of a moderately hot 84.4°F (29.1°C) in September, barely different from 86.7°F (30.4°C) in August. South Pasadena, in September, observes a steady average low-temperature of 63.7°F (17.6°C).Heat index
For most parts of September, the heat index is evaluated at a tropical 86°F (30°C). Prolonged exposure and physical activity might induce exhaustion, potentially causing heat cramps.Realize that the values for the heat index are set for shaded places and light winds. An exposure to direct sunlight may lift the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', reflects the feeling of heat when considering both air temperature and humidity. Additional elements including metabolic differences, the level of physical activity, and attire have a role in shaping the individual's temperature perception. Awareness is key; direct sunlight can enhance the weather's impact, possibly boosting the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for children. Young kids are often more at risk than adults as they tend to perspire less. Besides, their skin surface is larger relative to their small bodies, and their increased heat output from their active lifestyle compounds their risk.
Humidity
In September, the average relative humidity is 51%.Rainfall
In South Pasadena, in September, during 2.2 rainfall days, 0.12" (3mm) of precipitation is typically accumulated. In South Pasadena, during the entire year, the rain falls for 49.2 days and collects up to 8.23" (209mm) of precipitation.Snowfall
In South Pasadena, snow does not fall in January through November.Daylight
In September, the average length of the day is 12h and 22min.On the first day of the month, sunrise is at 6:26 am and sunset at 7:17 pm. On the last day of September, sunrise is at 6:46 am and sunset at 6:37 pm PDT.
Sunshine
In September, the average sunshine is 10.8h.UV index
The months with the highest UV index in South Pasadena are June through September, with an average maximum UV index of 6. A UV Index value of 6 to 7 symbolizes a high health vulnerability from unsafe exposure to UV radiation for the average person.Note: In September, a regular UV index of 6 translates into these guidelines:
Exercise precautions and adapt sun safety practices. Defence against skin and eye affliction is paramount. Limit direct sun exposure and seek shade between 10 a.m. and 4 p.m., the time of the most intense UV radiation, noting that shade structures may not provide total 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
Average temperature in September
South Pasadena, CA
- Average high temperature in September: 84.4°F
The warmest month (with the highest average high temperature) is August (86.7°F).
The month with the lowest average high temperature is December (63.1°F).
- Average low temperature in September: 63.7°F
The month with the highest average low temperature is August (65.7°F).
The coldest months (with the lowest average low temperature) are February and December (47.8°F).
Average pressure in September
South Pasadena, 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
South Pasadena, CA
- Average wind speed in September: 4.4mph
The windiest month (with the highest average wind speed) is April (5.7mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).
Average humidity in September
South Pasadena, CA
- Average humidity in September: 51%
The month with the highest relative humidity is June (59%).
The month with the lowest relative humidity is November (47%).
Average rainfall in September
South Pasadena, 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
South Pasadena, CA
- Average rainfall days in September: 2.2 days
The month with the highest number of rainy days is March (7.7 days).
The month with the least rainy days is June (1 days).
Average snowfall days in September
South Pasadena, 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
South Pasadena, CA
- Average daylight in September: 12h and 24min
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 48min
The months with the most sunshine are June and 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
South Pasadena, CA
- Average sunshine days in September: 26.1 days
The month with the most sunshine days is August (28.3 days).
The month with the least sunshine days is February (21 days).
Average UV index in September
South Pasadena, 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
South Pasadena, CA
- Average cloud cover in September: 7
The months with the most cloud cover are March and December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 4).
Average visibility in September
South Pasadena, 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).
