Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average sea temperature in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
The transition from August to September sees an average high-temperature of a still agreeable 72.7°F (22.6°C), indicating a minor variance from the prior month. In Redwood City, the expected average low-temperature for September is a moderate 56.7°F (13.7°C).Humidity
In Redwood City, the average relative humidity in September is 69%.Rainfall
In September, the rain falls for 2.4 days. Throughout September, 0.12" (3mm) of precipitation is accumulated. Throughout the year, there are 73.4 rainfall days, and 11.89" (302mm) of precipitation is accumulated.Ocean temperature
The months with the warmest seawater are August and September, with an average ocean temperature of 57.7°F (14.3°C).Note: Swimming at temperatures less than 50°F (10°C) in 57.7°F (14.3°C) is feasible with the right swimsuit; if not, expect cold shock and breathlessness. A quick swim at 55.4°F (13°C) without adequate warmth can be discomforting.
Daylight
In September, the average length of the day in Redwood City, California, is 12h and 25min.On the first day of the month, sunrise is at 6:40 am and sunset at 7:37 pm. On the last day of September, sunrise is at 7:04 am and sunset at 6:53 pm PDT.
Sunshine
In Redwood City, the average sunshine in September is 11h.UV index
The months with the highest UV index in Redwood City are June through September, with an average maximum UV index of 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for average individuals.Note: The maximum daily UV index, 5 in September, converts into the following recommendations:
Be vigilant - A duty to shield skin and eyes from injury exists. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. Enhance your sun protection with tightly woven, yet airy clothing.
Frequently asked questions
What is the average September temperature in Redwood City?
What is the average humidity in September in Redwood City?
How much does it rain in Redwood City in September?
When is the ocean warmest in Redwood City?
What is the water temperature in September in Redwood City?
How many hours of daylight does Redwood City have in September?
When is the sunrise / sunset in September in Redwood City?
How many hours of sunshine does Redwood City have in September?
When is the highest UV index in Redwood City?
What is the UV index intensity in September in Redwood City?
Average temperature in September
Redwood City, CA
- Average high temperature in September: 72.7°F
The warmest months (with the highest average high temperature) are July and August (73°F).
The month with the lowest average high temperature is December (55.9°F).
- Average low temperature in September: 56.7°F
The month with the highest average low temperature is September (56.7°F).
The coldest month (with the lowest average low temperature) is February (46°F).
Average pressure in September
Redwood City, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.92"Hg).
Average wind speed in September
Redwood City, CA
- Average wind speed in September: 5.5mph
The windiest month (with the highest average wind speed) is April (7.5mph).
The calmest months (with the lowest average wind speed) are August, September and October (5.5mph).
Average humidity in September
Redwood City, CA
- Average humidity in September: 69%
The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is October (68%).
Average rainfall in September
Redwood City, CA
- Average rainfall in September: 0.12"
The wettest month (with the highest rainfall) is February (2.36").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in September
Redwood City, CA
- Average rainfall days in September: 2.4 days
The month with the highest number of rainy days is March (12.8 days).
The month with the least rainy days is August (0.8 days).
Average sea temperature in September
Redwood City, CA
- Average sea temperature in September: 57.7°F
The best months for swimming (with the highest average sea temperature) are August and September (57.7°F).
The coldest month (with the lowest average sea temperature) is April (53.4°F).
Average daylight in September /
Average sunshine in September
Redwood City, 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 0min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in September
Redwood City, CA
- Average sunshine days in September: 26.4 days
The month with the most sunshine days is August (27.6 days).
The month with the least sunshine days is March (17.5 days).
Average UV index in September
Redwood City, CA
- Average UV index in September: 5
The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are November and December (UV index 3).
Average cloud cover in September
Redwood City, CA
- Average cloud cover in September: 12
The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 9).
Average visibility in September
Redwood City, 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).
Redwood City, California, USA
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