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 brings an average high-temperature of a still moderately hot 82.6°F (28.1°C), nearly identical to the preceding month. Throughout September, Bostonia witnesses a consistent average low-temperature of 63.9°F (17.7°C).Heat index
The heat index for September is estimated at 84.2°F (29°C). A sense of exhaustion might occur with extended exposure and activity, potentially causing heat cramps.From a standpoint of the heat index, values pertain to shaded conditions and mild breezes. Direct sunshine exposure could raise heat index values by as much as 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'real feel', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. This effect is personal, influenced by the individual's physical activity and heat sensitivity, shaped by factors including wind, attire, and metabolic variations. Consider that direct sun exposure can intensify the felt heat, adding potentially 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are extremely vital to babies and toddlers. Young ones often ignore the need to take a break and drink fluids. Thirst is a late-stage symptom of dehydration - hence, maintaining hydration, particularly during extended physical activities, is crucial.
Humidity
In September, the average relative humidity is 59%.Rainfall
In Bostonia, during September, the rain falls for 4.1 days and regularly aggregates up to 0.31" (8mm) of precipitation. In Bostonia, during the entire year, the rain falls for 56.1 days and collects up to 8.27" (210mm) of precipitation.Daylight
The average length of the day in September is 12h and 22min.On the first day of the month, sunrise is at 6:23 am and sunset at 7:12 pm. On the last day of September, sunrise is at 6:41 am and sunset at 6:33 pm PDT.
Sunshine
In Bostonia, the average sunshine in September is 10.4h.UV index
June through September, with an average maximum UV index of 6, are months with the highest UV index. A UV Index reading of 6 to 7 represents a high threat to health from exposure to the Sun's UV rays for average individuals.Note: The daily high UV index of 6 in September translates into this advice:
Undertake precautions and comply with sun safety standards. Protection from skin and eye injury is vital. Stay out of direct sunlight and seek shade between 10 a.m. and 4 p.m., when UV radiation is strongest, but remember that shade devices may not offer full sun protection. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.
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?
What is the average length of the day in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
What is the month with the highest UV index?
What is the UV index reading in September in Bostonia?
Average temperature in September
Bostonia, CA
- Average high temperature in September: 82.6°F
The warmest month (with the highest average high temperature) is August (83.8°F).
The month with the lowest average high temperature is December (63.7°F).
- Average low temperature in September: 63.9°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 (47.8°F).
Average pressure in September
Bostonia, CA
- Average pressure in September: 29.87"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are June and September (29.87"Hg).
Average wind speed in September
Bostonia, CA
- Average wind speed in September: 4.4mph
The windiest month (with the highest average wind speed) is April (5.5mph).
The calmest month (with the lowest average wind speed) is October (4.3mph).
Average humidity in September
Bostonia, CA
- Average humidity in September: 59%
The month with the highest relative humidity is May (66%).
The month with the lowest relative humidity is November (53%).
Average rainfall in September
Bostonia, CA
- Average rainfall in September: 0.31"
The wettest month (with the highest rainfall) is February (1.81").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in September
Bostonia, CA
- Average rainfall days in September: 4.1 days
The month with the highest number of rainy days is March (7.7 days).
The month with the least rainy days is June (1.4 days).
Average daylight in September /
Average sunshine in September
Bostonia, 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 month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 42min).
Average sunshine days in September
Bostonia, CA
- Average sunshine days in September: 24.1 days
The month with the most sunshine days is June (27.7 days).
The month with the least sunshine days is February (21.9 days).
Average UV index in September
Bostonia, 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
Bostonia, CA
- Average cloud cover in September: 9
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 7).
Average visibility in September
Bostonia, 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).
Bostonia, California, USA
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