September weather forecast
Fremont, CA

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A beautiful landscape of winding roads and serene residential estate in Fremont, California
A beautiful landscape of winding roads and serene residential estate in Fremont, California

Weather in September

September signals the end of summer and the beginning of fall in Fremont. The heat starts to dissipate, and the weather becomes more pleasant. The average sea temperature drops slightly but is still warm enough for beach activities. Cloud cover begins to increase again, but it does not overshadow the fact that Fremont still enjoys 11.1 hours of sunshine per day. The gentle decline in daylight is matched by an increase in humidity, averaging at 59%.

Temperature

As Fremont steps into September, the average high-temperature holds at a still moderately hot 80.6°F (27°C), hinting at a minor fluctuation from the prior month. With a notable difference from peak temperatures, an average of 56.3°F (13.5°C) marks the nights in September.

Heat index

The average heat index in September is calculated to be 82.4°F (28°C). Prolonged exposure combined with continuous activity could lead to exhaustion, and possibly heat cramps.
Metrics for the heat index primarily focus on shaded spots and light wind conditions. The direct sun can potentially cause the heat index to increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'felt air temperature', is achieved by amalgamating air temperature with the relative humidity readings. Elements such as metabolic variations, being pregnant, and physical activity can impact one's weather perception. Recognize that direct exposure to the sun can escalate the heat effect, potentially adding 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are especially vital to children. Children frequently do not understand the need for recuperation and hydration. Thirst, being a late manifestation of dehydration, underlines the need to hydrate frequently, especially when engaging in prolonged physical exercises.

Humidity

July and September, with an average relative humidity of 59%, are the least humid months in Fremont.

Rainfall

In September, the rain falls for 1.9 days. Throughout September, 0.08" (2mm) of precipitation is accumulated. Throughout the year, in Fremont, there are 49.6 rainfall days, and 3.86" (98mm) of precipitation is accumulated.

Ocean temperature

In September, the average ocean temperature is 57.6°F (14.2°C).
Note: Swimming in 57.6°F (14.2°C) feels unbearing at 55.4°F (13°C) and can be life-risking below 50°F (10°C), causing breathing issues and cold shock, depending on a person's capacity.

Daylight

In Fremont, the average length of the day in September is 12h and 25min.
On the first day of the month, sunrise is at 6:38 am and sunset at 7:36 pm. On the last day of September, in Fremont, sunrise is at 7:03 am and sunset at 6:51 pm PDT.

Sunshine

In Fremont, the average sunshine in September is 11.1h.

UV index

In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for the ordinary person.
Note: An average UV index of 5 in September transforms into this advice:
Make use of precautions - It is urged to ward off sun damage. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Arm yourself against UV rays' harm with protective apparel and UV-filtering shades.
Updated: Jun 29, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

In Fremont, 80.6°F (27°C) is the average high-temperature and 56.3°F (13.5°C) is the average low-temperature during September. The average heat index (a.k.a. 'apparent temperature', 'feels like'), which represents the influence of relative humidity on air temperature, in September is calculated to be 82.4°F (28°C).

What are the least humid months?

July and September, with an average relative humidity of 59%, are the least humid months in Fremont.

What is the average humidity in September?

In September, the average relative humidity is 59%.

How much does it rain in September?

In Fremont, during September, the rain falls for 1.9 days and regularly aggregates up to 0.08" (2mm) of precipitation.

What is the water temperature in September?

In September, the average ocean temperature is 57.6°F (14.2°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

How many hours of daylight does Fremont have in September?

In September, the average day length is 12h and 25min.

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:38 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:51 pm PDT.

How long on average sun shines in September?

In Fremont, the average sunshine duration in September is 11.1h.

How high is the UV index in September?

In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a moderate health threat from unprotected exposure to 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
Fremont, CA

Average temperature in September - Fremont, CA
  • Average high temperature in September: 80.6°F

The warmest month (with the highest average high temperature) is July (82.6°F).
The month with the lowest average high temperature is December (56.5°F).

  • Average low temperature in September: 56.3°F

The month with the highest average low temperature is August (56.8°F).
The coldest month (with the lowest average low temperature) is January (42.8°F).

Average pressure in September
Fremont, CA

Average pressure in September - Fremont, 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
Fremont, CA

Average wind speed in September - Fremont, CA
  • Average wind speed in September: 4.7mph

The windiest month (with the highest average wind speed) is May (6.1mph).
The calmest month (with the lowest average wind speed) is November (4.4mph).

Average humidity in September
Fremont, CA

Average humidity in September - Fremont, CA
  • Average humidity in September: 59%

The month with the highest relative humidity is March (72%).
The months with the lowest relative humidity are July and September (59%).

Average rainfall in September
Fremont, CA

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

The wettest months (with the highest rainfall) are January, February, March and December (0.67").
The driest months (with the least rainfall) are June, July and August (0.04").

Average rainfall days in September
Fremont, CA

Average rainfall days in September - Fremont, CA
  • Average rainfall days in September: 1.9 days

The month with the highest number of rainy days is March (8.9 days).
The month with the least rainy days is August (0.5 days).

Average sea temperature in September
Fremont, CA

Average sea temperature in September - Fremont, CA
  • Average sea temperature in September: 57.5°F

The best month for swimming (with the highest average sea temperature) is August (57.7°F).
The coldest months (with the lowest average sea temperature) are February and April (53.2°F).

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

Average daylight in September / Average sunshine in September - Fremont, 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 1min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).

Average sunshine days in September
Fremont, CA

Average sunshine days in September - Fremont, CA
  • Average sunshine days in September: 27.7 days

The month with the most sunshine days is July (30 days).
The month with the least sunshine days is March (20.7 days).

Average UV index in September
Fremont, CA

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

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

Average cloud cover in September
Fremont, CA

Average cloud cover in September - Fremont, CA
  • Average cloud cover in September: 10

The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 6).

Average visibility in September
Fremont, CA

Average visibility in September - Fremont, 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).

Fremont, California, USA

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