September weather forecastMenlo Park, CA
September
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.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
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: 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: 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: 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: 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: 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: 12h and 24min
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: 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: 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: 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: 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).
