April weather forecast and climate
South San Francisco, CA

A sign in large font of the South San Francisco City, California, on the hills over the scenic home setting below
A sign in large font of the South San Francisco City, California, on the hills over the scenic home setting below

Weather in April

April in South San Francisco, California, is an enjoyable spring month, with average temperature fluctuating between 49.3°F (9.6°C) and 61.3°F (16.3°C).

Temperature

In April, the average high-temperature is essentially the same as in March - an enjoyable 61.3°F (16.3°C). In April, the average low-temperature is 49.3°F (9.6°C).

Humidity

The average relative humidity in April is 75%.

Rainfall

In South San Francisco, it is raining for 5.3 days, with typically 0.2" (5mm) of accumulated precipitation. Throughout the year, there are 53.6 rainfall days, and 3.9" (99mm) of precipitation is accumulated.

Daylight

In April, the average length of the day in South San Francisco is 13.2h.

Sunshine

In April, the average sunshine in South San Francisco is 10.3h.

UV index

In April, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from unsafe exposure to the UV radiation for the average person.
Note: In April, the average maximum UV index of 4 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. 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 April in South San Francisco?

The average high-temperature, in April, is 61.3°F (16.3°C), while the average low-temperature is 49.3°F (9.6°C).

What is the average humidity in April in South San Francisco?

In April, the average relative humidity in South San Francisco, California, is 75%.

How much does it rain in South San Francisco in April?

In South San Francisco, California, in April, it is raining for 5.3 days, with typically 0.2" (5mm) of accumulated precipitation.

How many hours of daylight does South San Francisco have in April?

In April, the average length of the day is 13.2h.

How long on average sun shines in April in South San Francisco?

In April, the average sunshine in South San Francisco, California, is 10.3h.

What is the UV index intensity in April in South San Francisco?

The average daily maximum UV index in April in South San Francisco is 4. A UV Index value of 3 to 5 symbolizes a moderate health threat from unsafe exposure to the Sun's UV rays.

Average temperature in April
South San Francisco, CA

Average temperature in April - South San Francisco, CA
  • Average high temperature in April: 61.3°F

The warmest month (with the highest average high temperature) is September (70°F).
The month with the lowest average high temperature is December (55.6°F).

  • Average low temperature in April: 49.3°F

Months with the highest average low temperature are August and September (56.5°F).
The coldest months (with the lowest average low temperature) are January, February and December (47.8°F).

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Average pressure in April
South San Francisco, CA

Average pressure in April - South San Francisco, CA
  • Average pressure in April: 30.04"

The month with the highest atmospheric pressure is January (30.13").
The month with the lowest atmospheric pressure is September (29.92").

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Average wind speed in April
South San Francisco, CA

Average wind speed in April - South San Francisco, CA
  • Average wind speed in April: 8.5mph

The windiest month (with the highest average wind speed) is April (8.5mph).
The calmest month (with the lowest average wind speed) is September (6.2mph).

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Average humidity in April
South San Francisco, CA

Average humidity in April - South San Francisco, CA
  • Average humidity in April: 75%

The month with the highest relative humidity is August (78%).
Months with the lowest relative humidity are October and November (71%).

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Average rainfall in April
South San Francisco, CA

Average rainfall in April - South San Francisco, CA
  • Average rainfall in April: 0.2"

The wettest month (with the highest rainfall) is February (0.79").
The driest months (with the least rainfall) are June, July and August (0.04").

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Average rainfall days in April
South San Francisco, CA

Average rainfall days in April - South San Francisco, CA
  • Average rainfall days in April: 5.3 days

The month with the highest number of rainy days is March (9.4 days).
The month with the least rainy days is June (1.1 days).

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Average daylight in April /
Average sunshine in April
South San Francisco, CA

Average daylight in April / Average sunshine in April - South San Francisco, CA
  • Average daylight in April: 13.2h

The month with the longest days is June (Average daylight: 14.7h).
The month with the shortest days is December (Average daylight: 9.6h).

  • Average sunshine in April: 10.3h

The month with the most sunshine is July (Average sunshine: 11.7h).
The month with the least sunshine is December (Average sunshine: 5.8h).

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Average sunshine days in April
South San Francisco, CA

Average sunshine days in April - South San Francisco, CA
  • Average sunshine days in April: 23.1 days

Months with the most sunshine days are June, July and September (26.3 days).
The month with the least sunshine days is March (19.4 days).

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Average UV index in April
South San Francisco, CA

Average UV index in April - South San Francisco, CA
  • Average UV index in April: 4

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

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Average cloud cover in April
South San Francisco, CA

Average cloud cover in April - South San Francisco, CA
  • Average cloud cover in April: 28

The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is September (Cloud cover 16).

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Average visibility in April
South San Francisco, CA

Average visibility in April - South San Francisco, CA
  • Average visibility in April: 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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