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
September stands out as Hercules's warmest month, with an average high-temperature of 77.5°F (25.3°C) and a low-temperature of 56.7°F (13.7°C).Humidity
September and October, with an average relative humidity of 63%, are the least humid months in Hercules.Rainfall
In Hercules, during September, the rain falls for 2.3 days and regularly aggregates up to 0.12" (3mm) of precipitation. Throughout the year, in Hercules, there are 72.2 rainfall days, and 12.83" (326mm) of precipitation is accumulated.Ocean temperature
The month with the warmest seawater in Hercules, California, is September, with an average ocean temperature of 57°F (13.9°C).Note: Diving into 57°F (13.9°C) when it's under 50°F (10°C) can cause immediate cold shock symptoms, marked by hyperventilation.
Daylight
In September, the average length of the day is 12h and 25min.On the first day of the month, sunrise is at 6:39 am and sunset at 7:38 pm. On the last day of September, in Hercules, sunrise is at 7:04 am and sunset at 6:53 pm PDT.
Sunshine
The average sunshine in September in Hercules, California, is 10.9h.UV index
April through September, with an average maximum UV index of 5, are months with the highest UV index in Hercules, California. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for the ordinary person.Note: In September, a daily UV index of 5 turns into the following recommendations:
Undertake precautions - Guarding against sun damage is counselled. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the hottest time of year in Hercules?
What is the usual temperature for Hercules in September?
What is the least humid month in Hercules?
What is the average humidity in September in Hercules?
How much does it rain in Hercules in September?
What month is the ocean warmest in Hercules?
What is the water temperature in September in Hercules?
How many hours of daylight does Hercules have in September?
When are sunrise and sunset in September in Hercules?
How many hours of sunshine does Hercules have in September?
When is the highest UV index in Hercules?
What is the UV index reading in September in Hercules?
Average temperature in September
Hercules, CA
- Average high temperature in September: 77.5°F
The warmest month (with the highest average high temperature) is September (77.5°F).
The month with the lowest average high temperature is December (55.4°F).
- Average low temperature in September: 56.7°F
The month with the highest average low temperature is August (56.8°F).
The coldest months (with the lowest average low temperature) are January and December (43.9°F).
Average pressure in September
Hercules, 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
Hercules, CA
- Average wind speed in September: 5.7mph
The windiest month (with the highest average wind speed) is May (7.5mph).
The calmest month (with the lowest average wind speed) is November (4.8mph).
Average humidity in September
Hercules, CA
- Average humidity in September: 63%
The month with the highest relative humidity is March (74%).
The months with the lowest relative humidity are September and October (63%).
Average rainfall in September
Hercules, CA
- Average rainfall in September: 0.12"
The wettest month (with the highest rainfall) is February (2.76").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in September
Hercules, CA
- Average rainfall days in September: 2.3 days
The month with the highest number of rainy days is March (12.6 days).
The month with the least rainy days is August (1.1 days).
Average sea temperature in September
Hercules, CA
- Average sea temperature in September: 57°F
The best month for swimming (with the highest average sea temperature) is September (57°F).
The coldest month (with the lowest average sea temperature) is April (52.6°F).
Average daylight in September /
Average sunshine in September
Hercules, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in September: 10h and 5min
The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).
Average sunshine days in September
Hercules, CA
- Average sunshine days in September: 25.9 days
The month with the most sunshine days is August (27.3 days).
The month with the least sunshine days is March (16.4 days).
Average UV index in September
Hercules, CA
- Average UV index in September: 5
The months with the highest UV index are April, May, June, July, August and September (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Hercules, CA
- Average cloud cover in September: 13
The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 12).
Average visibility in September
Hercules, 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).
Hercules, California, USA
Weather forecast for your location
2. Allow the app to use your location