December weather forecast and climate
Gilroy, CA

A colorful sunset sky over the hilly region of Gilroy in California
A colorful sunset sky over the hilly region of Gilroy in California

Weather in December

December, the first month of the winter, in Gilroy, is also a moderate month, with average temperature varying between 57.6°F (14.2°C) and 41.2°F (5.1°C).

Temperature

With an average high-temperature of 57.6°F (14.2°C) and an average low-temperature of 41.2°F (5.1°C), December is the coldest month.

Humidity

In Gilroy, the average relative humidity is 71%.

Rainfall

The month with the most rainfall in Gilroy is December when the rain falls for 6.6 days and typically aggregates up to 0.83" (21mm) of precipitation.

Daylight

With an average of 9.7h of daylight, December has the shortest days of the year.

Sunshine

December has the least sunshine of the year, with an average of 6h of sunshine.

UV index

Months with the lowest UV index are January, February, November and December, with an average maximum UV index of 3. A UV Index estimate of 3 to 5 represents a medium health hazard from unsafe exposure to the UV radiation for the average person.
Note: In December, the average maximum UV index of 3 translate into the following recommendations:
Take precautions - Protection against sun damage is advised. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the coldest month in Gilroy?

The coldest month in Gilroy is December, with an average high-temperature of 57.6°F (14.2°C) and an average low-temperature of 41.2°F (5.1°C).

What is the temperature in December in Gilroy?

The average high-temperature, in December, in Gilroy, California, is 57.6°F (14.2°C), while the average low-temperature is 41.2°F (5.1°C).

What is the average humidity in December in Gilroy?

The average relative humidity in December in Gilroy, California, is 71%.

How much does it rain in Gilroy in December?

In December, in Gilroy, the rain falls for 6.6 days. Throughout December, 0.83" (21mm) of precipitation is accumulated.

What is the rainiest month in Gilroy?

December is the month with the most rainfall. Rain falls for 6.6 days and accumulates 0.83" (21mm) of precipitation.

What is the month with the shortest days in Gilroy?

December has the shortest days of the year, with an average of 9.7h of daylight.

What is the average length of the day in December in Gilroy?

The average length of the day in December in Gilroy is 9.7h.

What is the month with the least sunshine in Gilroy?

December has the least sunshine of the year in Gilroy, California, with an average of 6h of sunshine.

How many hours of sunshine does Gilroy have in December?

The average sunshine in December in Gilroy, California, is 6h.

What is the month with the lowest UV index in Gilroy?

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

What is the UV index reading in December in Gilroy?

The average daily maximum UV index in December in Gilroy is 3. A UV Index value of 3 to 5 symbolizes a medium health risk from the exposure to the Sun's UV rays.

Average temperature in December
Gilroy, CA

Average temperature in December - Gilroy, CA
  • Average high temperature in December: 57.6°F

The warmest month (with the highest average high temperature) is August (85.1°F).
The month with the lowest average high temperature is December (57.6°F).

  • Average low temperature in December: 41.2°F

Months with the highest average low temperature are August and September (54.1°F).
The coldest months (with the lowest average low temperature) are February and March (40.6°F).

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Average pressure in December
Gilroy, CA

Average pressure in December - Gilroy, CA
  • Average pressure in December: 30.11"

The month with the highest atmospheric pressure is January (30.14").
Months with the lowest atmospheric pressure are June, August and September (29.92").

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Average wind speed in December
Gilroy, CA

Average wind speed in December - Gilroy, CA
  • Average wind speed in December: 4.1mph

The windiest month (with the highest average wind speed) is May (5.3mph).
The calmest month (with the lowest average wind speed) is November (3.9mph).

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Average humidity in December
Gilroy, CA

Average humidity in December - Gilroy, CA
  • Average humidity in December: 71%

The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is September (57%).

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Average rainfall in December
Gilroy, CA

Average rainfall in December - Gilroy, CA
  • Average rainfall in December: 0.83"

The wettest month (with the highest rainfall) is December (0.83").
The driest months (with the least rainfall) are June, July and August (0").

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Average rainfall days in December
Gilroy, CA

Average rainfall days in December - Gilroy, CA
  • Average rainfall days in December: 6.6 days

The month with the highest number of rainy days is March (8.3 days).
The month with the least rainy days is August (0.6 days).

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Average daylight in December /
Average sunshine in December
Gilroy, CA

Average daylight in December / Average sunshine in December - Gilroy, CA
  • Average daylight in December: 9.7h

The month with the longest days is June (Average daylight: 14.7h).
The month with the shortest days is December (Average daylight: 9.7h).

  • Average sunshine in December: 6h

The month with the most sunshine is July (Average sunshine: 12.1h).
The month with the least sunshine is December (Average sunshine: 6h).

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Average sunshine days in December
Gilroy, CA

Average sunshine days in December - Gilroy, CA
  • Average sunshine days in December: 23.2 days

The month with the most sunshine days is July (29.9 days).
The month with the least sunshine days is March (21.4 days).

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Average UV index in December
Gilroy, CA

Average UV index in December - Gilroy, CA
  • Average UV index in December: 3

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are January, February, November and December (UV index 3).

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Average cloud cover in December
Gilroy, CA

Average cloud cover in December - Gilroy, CA
  • Average cloud cover in December: 34

The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 7).

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Average visibility in December
Gilroy, CA

Average visibility in December - Gilroy, CA
  • Average visibility in December: 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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