January weather forecast and climate
Hercules, CA

Weather in January

January, like December, is a moderate winter month in Hercules, California, with average temperature varying between 43.9°F (6.6°C) and 56.3°F (13.5°C).

Temperature

In January, the average high-temperature is relatively the same as in December - a still moderate 56.3°F (13.5°C). The average low-temperature, in January, is 43.9°F (6.6°C).

Humidity

The average relative humidity in Hercules, California, is 73%.

Rainfall

In Hercules, it is raining for 9.9 days, with typically 2.24" (57mm) of accumulated precipitation. In Hercules, during the entire year, the rain falls for 72.2 days and collects up to 12.83" (326mm) of precipitation.

Ocean temperature

In January, the average ocean temperature is 53.1°F (11.7°C).
Note: 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.

Daylight

The average length of the day in January is 9.9h.

Sunshine

In January, the average sunshine is 6h.

UV index

Months with the lowest UV index in Hercules are January, February, November and December, with an average maximum UV index of 3. A UV Index reading of 3 to 5 represents a moderate threat to health from the exposure to the Sun's UV rays for the ordinary person.
Note: The average daily UV index of 3 transform into the following instructions:
Take precautions - Protection against the skin and eye damage is obliged. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
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FAQ

What is the temperature in January in Hercules?

The average high-temperature, in January, is 56.3°F (13.5°C), while the average low-temperature is 43.9°F (6.6°C).

What is the average humidity in January in Hercules?

In January, the average relative humidity in Hercules, California, is 73%.

How much does it rain in Hercules in January?

In Hercules, during January, the rain falls for 9.9 days and regularly aggregates up to 2.24" (57mm) of precipitation.

How cold is the water in January in Hercules?

In January, the average ocean temperature in Hercules is 53.1°F (11.7°C). Swimming in 53.1°F (11.7°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

What is the average length of the day in January in Hercules?

In January, the average length of the day in Hercules is 9.9h.

How many hours of sunshine does Hercules have in January?

The average sunshine in January is 6h.

When is the lowest UV index in Hercules?

January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index in Hercules, California.

How high is the UV index in January in Hercules?

In Hercules, the average daily maximum UV index in January is 3. A UV Index estimate of 3 to 5 represents a moderate health threat from the exposure to the Sun's UV radiation.

Average temperature in January
Hercules, CA

Average temperature in January - Hercules, CA
  • Average high temperature in January: 56.3°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 January: 43.9°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).

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Average pressure in January
Hercules, CA

Average pressure in January - Hercules, CA
  • Average pressure in January: 30.13"

The month with the highest atmospheric pressure is January (30.13").
Months with the lowest atmospheric pressure are June, August and September (29.92").

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Average wind speed in January
Hercules, CA

Average wind speed in January - Hercules, CA
  • Average wind speed in January: 5.2mph

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).

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Average humidity in January
Hercules, CA

Average humidity in January - Hercules, CA
  • Average humidity in January: 73%

The month with the highest relative humidity is March (74%).
Months with the lowest relative humidity are September and October (63%).

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Average rainfall in January
Hercules, CA

Average rainfall in January - Hercules, CA
  • Average rainfall in January: 2.24"

The wettest month (with the highest rainfall) is February (2.76").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in January
Hercules, CA

Average rainfall days in January - Hercules, CA
  • Average rainfall days in January: 9.9 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).

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Average sea temperature in January
Hercules, CA

Average sea temperature in January - Hercules, CA
  • Average sea temperature in January: 53°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).

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Average daylight in January /
Average sunshine in January
Hercules, CA

Average daylight in January / Average sunshine in January - Hercules, CA
  • Average daylight in January: 9.9h

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

  • Average sunshine in January: 6h

The month with the most sunshine is July (Average sunshine: 11.9h).
The month with the least sunshine is December (Average sunshine: 5.7h).

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Average sunshine days in January
Hercules, CA

Average sunshine days in January - Hercules, CA
  • Average sunshine days in January: 20.5 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).

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Average UV index in January
Hercules, CA

Average UV index in January - Hercules, CA
  • Average UV index in January: 3

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

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Average cloud cover in January
Hercules, CA

Average cloud cover in January - Hercules, CA
  • Average cloud cover in January: 34

The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 12).

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Average visibility in January
Hercules, CA

Average visibility in January - Hercules, CA
  • Average visibility in January: 6mi

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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