Hercules
California, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Hercules, CA

Ocean temperature

With an average ocean temperature of 57°F (13.9°C), September is the month with the warmest seawater in Hercules, California.
Note: Swimming in 57°F (13.9°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.

Daylight

In September, the average length of the day in Hercules is 12.4h.

When is the ocean warmest in Hercules?

The month with the warmest seawater in Hercules is September, with an average ocean temperature of 57°F (13.9°C).

What is the water temperature in September in Hercules?

In September, the average ocean temperature in Hercules is 57°F (13.9°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 Hercules have in September?

The average length of the day in September in Hercules, California, is 12.4h.
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 - Hercules, CA
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 14.8h).
The month with shortest days is December (Average daylight: 9.6h).