Monthly weather forecast and climate
Saint Helena, CA

Weather in January

January is a mild winter month in Saint Helena, California, with average temperature fluctuating between 39.7°F (4.3°C) and 56.8°F (13.8°C). In Saint Helena, the average high-temperature is almost the same as in December - a mild 56.8°F (13.8°C). Weather in January »

Weather in February

February, the last month of the winter, in Saint Helena, is also a moderate month, with average temperature fluctuating between 39.7°F (4.3°C) and 59.2°F (15.1°C). In February, the average high-temperature is essentially the same as in January - a still mild 59.2°F (15.1°C). Weather in February »

Weather in March

The first month of the spring, March, is an enjoyable month in Saint Helena, California, with average temperature ranging between min 40.5°F (4.7°C) and max 61.5°F (16.4°C). In March, the average high-temperature is essentially the same as in February - an enjoyable 61.5°F (16.4°C). Weather in March »

Weather in April

April is a pleasant spring month in Saint Helena, California, with average temperature ranging between min 43.2°F (6.2°C) and max 68°F (20°C). In Saint Helena, the average high-temperature in April slightly increases, from an enjoyable 61.5°F (16.4°C) in March, to a pleasant 68°F (20°C). Weather in April »

Weather in May

May, the last month of the spring, in Saint Helena, is a warm month, with temperature in the range of an average high of 74.1°F (23.4°C) and an average low of 46.9°F (8.3°C). In May, the average high-temperature slightly increases, from an agreeable 68°F (20°C) in April, to a moderately hot 74.1°F (23.4°C). Weather in May »

Weather in June

June, the first month of the summer, in Saint Helena, is also a moderately hot month, with average temperature varying between 83.8°F (28.8°C) and 52.5°F (11.4°C). In June, the average high-temperature increases, from a warm 74.1°F (23.4°C) in May, to a still moderately hot 83.8°F (28.8°C). Weather in June »

Weather in July

July in Saint Helena, California, is a tropical summer month, with average temperature varying between 88.3°F (31.3°C) and 53.8°F (12.1°C). July is the warmest month, with an average high-temperature of 88.3°F (31.3°C) and an average low-temperature of 53.8°F (12.1°C). In July, the average heat index is evaluated at a tropical 93.6°F (34.2°C). Weather in July »

Weather in August

The last month of the summer, August, is also a hot month in Saint Helena, California, with average temperature varying between 54.1°F (12.3°C) and 88°F (31.1°C). In August, the average high-temperature is relatively the same as in July - a still tropical 88°F (31.1°C). Weather in August »

Weather in September

September, the first month of the autumn, in Saint Helena, is still a warm month, with average temperature varying between 54.3°F (12.4°C) and 85.3°F (29.6°C). In September, the average high-temperature is almost the same as in August - a moderately hot 85.3°F (29.6°C). Weather in September »

Weather in October

October, the same as September, is another warm autumn month in Saint Helena, California, with temperature in the range of an average high of 75°F (23.9°C) and an average low of 50.9°F (10.5°C). In October, the average high-temperature drops, from 85.3°F (29.6°C) in September, to a still warm 75°F (23.9°C). Weather in October »

Weather in November

The last month of the autumn, November, is also an enjoyable month in Saint Helena, California, with average temperature ranging between min 44.1°F (6.7°C) and max 63.5°F (17.5°C). In November, the average high-temperature decreases, from a moderately hot 75°F (23.9°C) in October, to a comfortable 63.5°F (17.5°C). Weather in November »

Weather in December

The first month of the winter, December, is still a cool month in Saint Helena, California, with average temperature ranging between min 39.6°F (4.2°C) and max 54.5°F (12.5°C). The coldest month is December, with an average high-temperature of 54.5°F (12.5°C) and an average low-temperature of 39.6°F (4.2°C). Weather in December »
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FAQ

How much does it rain in Saint Helena?

In Saint Helena, during the entire year, the rain falls for 76.2 days and collects up to 16.93" (430mm) of precipitation.

How much does it snow in Saint Helena?

Throughout the year, in Saint Helena, 0.04" (1mm) of snow is accumulated.

When it does not snow in Saint Helena?

In Saint Helena snow does not fall in January, February, April through December.

What are the months with the lowest UV index in Saint Helena?

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

What is the wettest month in Saint Helena?

The month with the most rainfall in Saint Helena is February when the rain falls for 9.3 days and typically aggregates up to 3.7" (94mm) of precipitation.

What is the most humid month in Saint Helena?

With an average relative humidity of 76%, March is the most humid month.

When does it snow in Saint Helena?

March is the only month when snow falls in Saint Helena, California.

What is the snowiest month in Saint Helena?

The month with the most snowfall in Saint Helena is March when snow falls for 0.2 days and typically aggregates up to 0.04" (1mm) of snow.

When are the longest days in Saint Helena?

With an average of 14.8h of daylight, June has the longest days of the year in Saint Helena, California.

What are the months with the highest UV index in Saint Helena?

June through August, with an average maximum UV index of 6, are months with the highest UV index in Saint Helena, California.

What is the warmest month in Saint Helena?

July is the warmest month in Saint Helena, with an average high-temperature of 88.3°F (31.3°C) and an average low-temperature of 53.8°F (12.1°C).

What is the driest month in Saint Helena?

The only month without rainfall in Saint Helena, California, is July.

What month has the most sunshine in Saint Helena?

The month with the most sunshine in Saint Helena, California, is July, with an average of 11.9h of sunshine.

When does it rain in Saint Helena?

January through June, August through December are months with rainfall.

What is the least humid month in Saint Helena?

September is the least humid month in Saint Helena, with an average relative humidity of 53%.

What is the coldest month in Saint Helena?

With an average high-temperature of 54.5°F (12.5°C) and an average low-temperature of 39.6°F (4.2°C), December is the coldest month.

What is the month with the shortest days in Saint Helena?

With an average of 9.5h of daylight, December has the shortest days of the year.

What is the month with the least sunshine in Saint Helena?

With an average of 5.3h of sunshine, December has the least sunshine of the year in Saint Helena.

Average temperature
Saint Helena, CA

Average temperature - Saint Helena, CA

The warmest month (with the highest average high temperature) is July (88.3°F).
The month with the lowest average high temperature is December (54.5°F).

The month with the highest average low temperature is September (54.3°F).
The coldest month (with the lowest average low temperature) is December (39.6°F).

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Average pressure
Saint Helena, CA

Average pressure - Saint Helena, CA

The month with the highest atmospheric pressure is January (30.14").
Months with the lowest atmospheric pressure are June, August and September (29.91").

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Average wind speed
Saint Helena, CA

Average wind speed - Saint Helena, CA

The windiest month (with the highest average wind speed) is May (5.8mph).
The calmest month (with the lowest average wind speed) is November (4.3mph).

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Average humidity
Saint Helena, CA

Average humidity - Saint Helena, CA

The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is September (53%).

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Average rainfall
Saint Helena, CA

Average rainfall - Saint Helena, CA

The wettest month (with the highest rainfall) is February (3.7").
The driest month (with the least rainfall) is July (0").

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Average rainfall days
Saint Helena, CA

Average rainfall days - Saint Helena, CA

The month with the highest number of rainy days is March (13.5 days).
The month with the least rainy days is August (0.3 days).

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Average snowfall
Saint Helena, CA

Average snowfall - Saint Helena, CA

The month with the highest snowfall is March (0.04").
Months with the least snowfall are January, February, April, May, June, July, August, September, October, November and December (0").

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Average snowfall days
Saint Helena, CA

Average snowfall days - Saint Helena, CA

The month with the highest number of snowfall days is March (0.2 days).
Months with the least snowfall days are January, February, April, May, June, July, August, September, October, November and December (0 days).

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Average daylight / Average sunshine
Saint Helena, CA

Average daylight / Average sunshine - Saint Helena, CA

The month with the longest days is June (Average daylight: 14.8h).
The month with the shortest days is December (Average daylight: 9.5h).

The month with the most sunshine is July (Average sunshine: 11.9h).
The month with the least sunshine is December (Average sunshine: 5.3h).

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Average sunshine days
Saint Helena, CA

Average sunshine days - Saint Helena, CA

The month with the most sunshine days is July (30 days).
The month with the least sunshine days is March (15.9 days).

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Average UV index
Saint Helena, CA

Average UV index - Saint Helena, CA

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 visibility
Saint Helena, CA

Average visibility - Saint Helena, CA

Months with the highest visibility are February, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January and March (5mi).

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