September weather forecast
Bystrom, CA

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Weather in September

The first month of the autumn, September, is still a tropical month in Bystrom, California, with temperature in the range of an average high of 90.9°F (32.7°C) and an average low of 59.9°F (15.5°C).

Temperature

With the arrival of September, Bystrom notices a mild change in the average high-temperature, sliding from August's very hot 96.4°F (35.8°C) to a tropical 90.9°F (32.7°C). Bystrom's average nighttime temperatures present a clear contrast to its daytime highs, measured at a moderate 59.9°F (15.5°C) in September.

Heat index

In September, the heat index is appraised at a tropical 93.2°F (34°C). Ensure extra safety steps, heat exhaustion and heat cramps are likely. Long activity might lead to heatstroke.
When referencing the heat index, its values are suitable for shady environments and light breezes. Exposure to unobstructed sunshine could lead to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'real feel', is a measure that combines air temperature and relative humidity into a single value that indicates how hot the weather feels. Physical activity, clothing, and metabolic variations are additional factors that impact an individual's perception of temperature. When directly under the sun, the weather's impact can intensify, possibly boosting the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young individuals usually face more risks than adults due to their lower sweat production. Their large skin surface area relative to their tiny bodies and high heat production from their activities adds to their risk.

Humidity

The average relative humidity in September is 41%.

Rainfall

In September, in Bystrom, the rain falls for 1.6 days. Throughout September, 0.08" (2mm) of precipitation is accumulated. In Bystrom, during the entire year, the rain falls for 54.3 days and collects up to 6.54" (166mm) of precipitation.

Daylight

In Bystrom, the average length of the day in September is 12h and 25min.
On the first day of September, sunrise is at 6:34 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:59 am and sunset at 6:47 pm PDT.

Sunshine

In Bystrom, the average sunshine in September is 11.5h.

UV index

The average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health hazard from exposure to the Sun's UV rays for ordinary individuals.
Note: A maximum high UV index of 6 in September translates into the following recommendations:
Resist extreme sun exposure. Guarding against solar damage is essential. Be aware that the sun's UV radiation is strongest between 10 a.m. and 4 p.m. and try to reduce direct sun exposure during this period as much as possible. A hat with a broad brim is indispensable, filtering out up to half of UV rays.

Frequently asked questions

How hot is it in Bystrom in September?

During September, Bystrom experiences an average high-temperature of 90.9°F (32.7°C) and a low-temperature of 59.9°F (15.5°C). The average heat index (a.k.a. 'real feel', 'apparent temperature'), which calculates the temperature value influenced by the moisture in the air, in September is appraised at 93.2°F (34°C).

What is the average humidity in September in Bystrom?

In Bystrom, California, the average relative humidity in September is 41%.

How many days does it rain in September in Bystrom?

In Bystrom, California, in September, it is raining for 1.6 days, with typically 0.08" (2mm) of accumulated precipitation.

What is the average length of the day in September in Bystrom?

The average day length in September in Bystrom, California, is 12h and 25min.

What time are sunrise and sunset in September in Bystrom?

In September, on the first day of the month, sunrise is at 6:34 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:59 am and sunset at 6:47 pm PDT.

How long on average sun shines in September in Bystrom?

In Bystrom, the average sunshine duration in September is 11.5h.

How high is the UV index in September in Bystrom?

The average daily maximum UV index in September in Bystrom is 6. A UV Index reading of 6 to 7 represents a high health risk from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Bystrom, CA

Average temperature in September - Bystrom, CA
  • Average high temperature in September: 90.9°F

The warmest month (with the highest average high temperature) is July (97.7°F).
The month with the lowest average high temperature is December (55.6°F).

  • Average low temperature in September: 59.9°F

The month with the highest average low temperature is July (62.1°F).
The coldest months (with the lowest average low temperature) are January and December (41.9°F).

Average pressure in September
Bystrom, CA

Average pressure in September - Bystrom, CA
  • Average pressure in September: 29.93"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
Bystrom, CA

Average wind speed in September - Bystrom, CA
  • Average wind speed in September: 5.8mph

The windiest month (with the highest average wind speed) is June (7.3mph).
The calmest month (with the lowest average wind speed) is November (5.2mph).

Average humidity in September
Bystrom, CA

Average humidity in September - Bystrom, CA
  • Average humidity in September: 41%

The month with the highest relative humidity is January (72%).
The month with the lowest relative humidity is July (37%).

Average rainfall in September
Bystrom, CA

Average rainfall in September - Bystrom, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is March (1.3").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in September
Bystrom, CA

Average rainfall days in September - Bystrom, CA
  • Average rainfall days in September: 1.6 days

The month with the highest number of rainy days is March (10.3 days).
The month with the least rainy days is August (0.9 days).

Average daylight in September /
Average sunshine in September
Bystrom, CA

Average daylight in September / Average sunshine in September - Bystrom, 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 36min).

  • Average sunshine in September: 11h and 3min

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
Bystrom, CA

Average sunshine days in September - Bystrom, CA
  • Average sunshine days in September: 27.1 days

The month with the most sunshine days is August (29.2 days).
The month with the least sunshine days is March (19.6 days).

Average UV index in September
Bystrom, CA

Average UV index in September - Bystrom, CA
  • Average UV index in September: 6

The months with the highest UV index are June, July and August (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 3).

Average cloud cover in September
Bystrom, CA

Average cloud cover in September - Bystrom, CA
  • Average cloud cover in September: 6

The month with the most cloud cover is March (Cloud cover 33).
The month with the least cloud cover is July (Cloud cover 4).

Average visibility in September
Bystrom, CA

Average visibility in September - Bystrom, 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).

Bystrom, California, USA

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