September weather forecast
Hollister, CA

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Weather in September

The first month of the autumn, September, is still a warm month in Hollister, California, with an average temperature varying between 85.1°F (29.5°C) and 54.9°F (12.7°C).

Temperature

The transition into September reveals an average high-temperature of a warm 85.1°F (29.5°C), mirroring a close resemblance to August. Hollister's September nights cool down significantly from the day's heat, to an average low-temperature of 54.9°F (12.7°C).

Heat index

The heat index in September is evaluated at a tropical 87.8°F (31°C). With extended exposure and activity, one might feel exhausted and experience heat cramps.
Understanding the heat index involves considering values for shaded locales with light wind. The heat index may scale up by 15 Fahrenheit (8 Celsius) degrees with direct sun exposure.
Note: The heat index, also known as 'real feel' or 'felt air temperature', takes into account both air temperature and humidity to illustrate what people actually feel. Additional elements including metabolic differences, the level of physical activity, and attire have a role in shaping the individual's temperature perception. When you're directly under the sun's rays, remember that the heat index may surge by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Youngsters generally face more threats than adults given their lesser ability to sweat. Coupled with their larger skin surface relative to their small bodies and higher heat production due to their activities, they are more endangered.

Humidity

In Hollister, California, the average relative humidity in September is 54%.

Rainfall

In Hollister, in September, it is raining for 1.5 days, with typically 0.08" (2mm) of accumulated precipitation. Throughout the year, there are 59.2 rainfall days, and 8.66" (220mm) of precipitation is accumulated.

Daylight

In Hollister, the average length of the day in September is 12h and 24min.
On the first day of the month, sunrise is at 6:37 am and sunset at 7:33 pm. On the last day of September, sunrise is at 7:00 am and sunset at 6:49 pm PDT.

Sunshine

The average sunshine in September in Hollister is 11.4h.

UV index

The average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for average individuals.
Note: An average maximum UV index of 5 in September leads to these recommendations:
Take care. Persons with lighter skin might suffer burns in less than 30 minutes. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Employ a wide-brim hat for potent defense against up to 50% of UV rays.
Updated: Jul 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot does it get in September?

The high-temperature, in September, in Hollister, records 85.1°F (29.5°C), while the low-temperature is 54.9°F (12.7°C). In September, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which takes the relative humidity and factors it into the air temperature reading, is evaluated at 87.8°F (31°C).

What is the average humidity in September?

The average relative humidity in September is 54%.

How many days does it rain in September?

In Hollister, during September, the rain falls for 1.5 days and regularly aggregates up to 0.08" (2mm) of precipitation.

What is the average length of the day in September?

In September, the average day length is 12h and 24min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 6:37 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:49 pm PDT.

How long on average sun shines in September?

In Hollister, the average sunshine duration in September is 11.4h.

What is the UV index reading in September?

In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate health threat from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Hollister, CA

Average temperature in September - Hollister, CA
  • Average high temperature in September: 85.1°F

The warmest month (with the highest average high temperature) is July (87.8°F).
The month with the lowest average high temperature is December (57.4°F).

  • Average low temperature in September: 54.9°F

The month with the highest average low temperature is August (55.4°F).
The coldest months (with the lowest average low temperature) are March and December (40.3°F).

Average pressure in September
Hollister, CA

Average pressure in September - Hollister, CA
  • Average pressure in September: 29.92"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).

Average wind speed in September
Hollister, CA

Average wind speed in September - Hollister, CA
  • Average wind speed in September: 4.2mph

The windiest month (with the highest average wind speed) is May (5.5mph).
The calmest month (with the lowest average wind speed) is November (3.7mph).

Average humidity in September
Hollister, CA

Average humidity in September - Hollister, CA
  • Average humidity in September: 54%

The month with the highest relative humidity is March (73%).
The month with the lowest relative humidity is July (53%).

Average rainfall in September
Hollister, CA

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

The wettest month (with the highest rainfall) is December (1.57").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in September
Hollister, CA

Average rainfall days in September - Hollister, CA
  • Average rainfall days in September: 1.5 days

The month with the highest number of rainy days is March (11.6 days).
The month with the least rainy days is August (0.3 days).

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

Average daylight in September / Average sunshine in September - Hollister, CA
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 36min).
The month with the shortest days is December (Average daylight: 9h and 42min).

  • Average sunshine in September: 11h 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 6min).

Average sunshine days in September
Hollister, CA

Average sunshine days in September - Hollister, CA
  • Average sunshine days in September: 27.8 days

The month with the most sunshine days is August (30.3 days).
The month with the least sunshine days is March (18.6 days).

Average UV index in September
Hollister, CA

Average UV index in September - Hollister, CA
  • Average UV index in September: 5

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).

Average cloud cover in September
Hollister, CA

Average cloud cover in September - Hollister, CA
  • Average cloud cover in September: 7

The month with the most cloud cover is March (Cloud cover 34).
The months with the least cloud cover are July and August (Cloud cover 5).

Average visibility in September
Hollister, CA

Average visibility in September - Hollister, 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).

Hollister, California, USA

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