Climate and monthly weather forecast
Saint Helena, CA

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Weather in January

January is a refreshing winter month in Saint Helena, California, with an average temperature fluctuating between 39.7°F (4.3°C) and 56.8°F (13.8°C). The average high-temperature during January is a mild 56.8°F (13.8°C), almost matching the conditions of the preceding month. Weather in January »

Weather in February

February, the last month of the winter in Saint Helena, is also a moderate month, with an average temperature ranging between min 39.7°F (4.3°C) and max 59.2°F (15.1°C). The average high-temperature during February registers at a still moderate 59.2°F (15.1°C), maintaining a close resemblance to the previous month. Weather in February »

Weather in March

March, the first month of the spring in Saint Helena, is an enjoyable month, with temperature in the range of an average high of 61.5°F (16.4°C) and an average low of 40.5°F (4.7°C). Saint Helena notes an average high-temperature of an enjoyable 61.5°F (16.4°C) in March, hardly diverging from February. Weather in March »

Weather in April

April in Saint Helena, California, is a pleasant spring month, with an average temperature fluctuating between 68°F (20°C) and 43.2°F (6.2°C). April's onset brings a subtle temperature rise, moving 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 moderately hot month, with an average temperature ranging between min 46.9°F (8.3°C) and max 74.1°F (23.4°C). May introduces a minor temperature shift, with average high-temperatures adjusting from April's pleasant 68°F (20°C) to a moderately hot 74.1°F (23.4°C). Weather in May »

Weather in June

The first month of the summer, June, is still a warm month in Saint Helena, California, with an average temperature ranging between max 83.8°F (28.8°C) and min 52.5°F (11.4°C). June signals a shift in the average high-temperature, moving from May's 74.1°F (23.4°C) to a still warm 83.8°F (28.8°C). Weather in June »

Weather in July

July in Saint Helena, California, is a hot summer month, with temperature in the range of an average high of 88.3°F (31.3°C) and an average low of 53.8°F (12.1°C). The warmest temperatures occur during July, when averages reach a peak of 88.3°F (31.3°C) and a low of 53.8°F (12.1°C). For most parts of July, the heat index is appraised at a hot 93.2°F (34°C). Weather in July »

Weather in August

August, the last month of the summer in Saint Helena, is also a hot month, with an average temperature fluctuating between 88°F (31.1°C) and 54.1°F (12.3°C). Saint Helena marks the start of August with an average high-temperature of a still tropical 88°F (31.1°C), hinting at a slight fluctuation from July's 88.3°F (31.3°C). Weather in August »

Weather in September

The first month of the autumn, September, is also a moderately hot month in Saint Helena, California, with an average temperature ranging between max 85.3°F (29.6°C) and min 54.3°F (12.4°C). The onset of September brings an average high-temperature of a warm 85.3°F (29.6°C), nearly matching the August temperature. Weather in September »

Weather in October

October, like September, in Saint Helena, California, is another warm autumn month, 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). The arrival of October corresponds with a temperature reduction, down from September's warm 85.3°F (29.6°C) to a still moderately hot 75°F (23.9°C). Weather in October »

Weather in November

November, the last month of the autumn in Saint Helena, is another comfortable month, with temperature in the range of an average high of 63.5°F (17.5°C) and an average low of 44.1°F (6.7°C). The start of November involves a temperature drop, moving from a moderately hot 75°F (23.9°C) in October to an enjoyable 63.5°F (17.5°C). Weather in November »

Weather in December

December, the first month of the winter in Saint Helena, is also a fresh month, with an average temperature ranging between min 39.6°F (4.2°C) and max 54.5°F (12.5°C). With its high average temperature of 54.5°F (12.5°C) and a low of 39.6°F (4.2°C), December is regarded as the coldest month. Weather in December »

Frequently asked questions

How much does it rain?

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

When it does not snow?

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

How much does it snow in Saint Helena?

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

What is the month with the lowest UV index?

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

What is the wettest month?

February is the month with the most rainfall. Rain falls for 9.3 days and accumulates 3.7" (94mm) of precipitation.

What is the most humid month?

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

When does it snow?

March is the only month when snow falls.

What is the snowiest month?

March is the month with the most snowfall. Snow falls for 0.2 days and accumulates 0.04" (1mm) of snow.

When is Daylight Saving Time (DST)?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from PST to PDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from PDT to PST.

When are the longest days?

With an average of 14h and 48min of daylight, June has the longest days of the year.

When is the highest UV index?

The months with the highest UV index are June through August, with an average maximum UV index of 6.

What is the hottest time of year?

With average high and low temperatures of 88.3°F (31.3°C) and 53.8°F (12.1°C) respectively, July is Saint Helena's warmest month.

What is the driest month?

The only month without rainfall is July.

What month has the most sunshine?

July has the most sunshine of the year, with an average of 11.9h of sunshine.

When does it rain?

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

What is the least humid month?

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

What part of the year is the coldest?

Temperature readings reach their annual highs in December, averaging 54.5°F (12.5°C) and a minimum average of 39.6°F (4.2°C).

What is the month with the shortest days?

The month with the shortest days in Saint Helena is December, with an average of 9h and 30min of daylight.

What is the month with the least sunshine?

December has the least sunshine of the year, with an average of 5.3h of sunshine.

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).

Average pressure
Saint Helena, CA

Average pressure - Saint Helena, CA

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

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).

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%).

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").

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).

Average snowfall
Saint Helena, CA

Average snowfall - Saint Helena, CA

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

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).
The months with the least snowfall days are January, February, April, May, June, July, August, September, October, November and December (0 days).

Average daylight / Average sunshine
Saint Helena, CA

Average daylight / Average sunshine - Saint Helena, CA

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 18min).

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).

Average UV index
Saint Helena, CA

Average UV index - Saint Helena, CA

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

Average visibility
Saint Helena, CA

Average visibility - Saint Helena, CA

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

Saint Helena, California, USA

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