September weather forecast
Menlo Park, CA

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Weather in September

September, the first month of the autumn in Menlo Park, is still a warm month, with an average temperature varying between 76.5°F (24.7°C) and 56.7°F (13.7°C).

Temperature

In September, Menlo Park notes an average high-temperature of a still moderately hot 76.5°F (24.7°C), hardly different from the preceding month. An average minimum temperature of 56.7°F (13.7°C) marks the month of September.

Humidity

The months with the lowest humidity are September and October, with an average relative humidity of 65%.

Rainfall

In September, the rain falls for 2.1 days. Throughout September, 0.08" (2mm) of precipitation is accumulated. Throughout the year, there are 63.3 rainfall days, and 9.53" (242mm) of precipitation is accumulated.

Daylight

In Menlo Park, the average length of the day in September is 12h and 25min.
On the first day of September, sunrise is at 6:39 am and sunset at 7:37 pm. On the last day of the month, sunrise is at 7:04 am and sunset at 6:52 pm PDT.

Sunshine

In September, the average sunshine is 11h.

UV index

The months with the highest UV index are April through October, with an average maximum UV index of 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for the average person.
Note: The maximum daily UV index of 5 during September translates into the following directions:
Undertake precautions - It is suggested to shield oneself from sunburn. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
Updated: Jun 14, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Menlo Park in September?

The average high-temperature and low-temperature during September are 76.5°F (24.7°C) and 56.7°F (13.7°C) respectively.

What are the least humid months in Menlo Park?

The months with the lowest humidity are September and October, with an average relative humidity of 65%.

What is the average humidity in September?

In September, the average relative humidity is 65%.

How many days does it rain in September?

In Menlo Park, in September, it is raining for 2.1 days, with typically 0.08" (2mm) of accumulated precipitation.

How many hours of daylight does Menlo Park have in September?

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

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:39 am and sunset at 7:37 pm. On the last day of the month, sunrise is at 7:04 am and sunset at 6:52 pm PDT.

How many hours of sunshine does Menlo Park have in September?

In Menlo Park, the average sunshine duration in September is 11h.

What is the month with the highest UV index?

The months with the highest UV index in Menlo Park are April through October, with an average maximum UV index of 5.

What is the UV index intensity in September?

In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a medium 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
Menlo Park, CA

Average temperature in September - Menlo Park, CA
  • Average high temperature in September: 76.5°F

The warmest months (with the highest average high temperature) are July and August (77.5°F).
The month with the lowest average high temperature is December (56.3°F).

  • Average low temperature in September: 56.7°F

The month with the highest average low temperature is August (57°F).
The coldest months (with the lowest average low temperature) are January and February (45.1°F).

Average pressure in September
Menlo Park, CA

Average pressure in September - Menlo Park, 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 and September (29.92"Hg).

Average wind speed in September
Menlo Park, CA

Average wind speed in September - Menlo Park, CA
  • Average wind speed in September: 4.9mph

The windiest months (with the highest average wind speed) are April and May (6.5mph).
The calmest months (with the lowest average wind speed) are September and October (4.9mph).

Average humidity in September
Menlo Park, CA

Average humidity in September - Menlo Park, CA
  • Average humidity in September: 65%

The month with the highest relative humidity is March (74%).
The months with the lowest relative humidity are September and October (65%).

Average rainfall in September
Menlo Park, CA

Average rainfall in September - Menlo Park, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is February (2.01").
The driest month (with the least rainfall) is July (0").

Average rainfall days in September
Menlo Park, CA

Average rainfall days in September - Menlo Park, CA
  • Average rainfall days in September: 2.1 days

The month with the highest number of rainy days is March (12.3 days).
The month with the least rainy days is August (0.6 days).

Average daylight in September /
Average sunshine in September
Menlo Park, CA

Average daylight in September / Average sunshine in September - Menlo Park, 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 0min

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
Menlo Park, CA

Average sunshine days in September - Menlo Park, CA
  • Average sunshine days in September: 27.6 days

The month with the most sunshine days is July (30.2 days).
The month with the least sunshine days is March (18 days).

Average UV index in September
Menlo Park, CA

Average UV index in September - Menlo Park, CA
  • Average UV index in September: 5

The months with the highest UV index are April, May, June, July, August, September and October (UV index 5).
The months with the lowest UV index are February, November and December (UV index 3).

Average cloud cover in September
Menlo Park, CA

Average cloud cover in September - Menlo Park, CA
  • Average cloud cover in September: 11

The months with the most cloud cover are March and December (Cloud cover 34).
The month with the least cloud cover is July (Cloud cover 6).

Average visibility in September
Menlo Park, CA

Average visibility in September - Menlo Park, 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).

Menlo Park, California, USA

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