As of 00:44 PDT

Weather in St. Helena, CA

58°

St. Helena, Sunday, 9 August, 00:44

Clear. Feels like 58°. High 93°, low 58°.

Pressure29.85 inHg

Wind2.5 mph W

Humidity83%

Visibility6.2 mi

Dew point53°

See detailed hourly forecast

Monthly outlook for St. Helena, CA: average high 88.3°, average low 54.6°. That is 2.5° above the climate normal for August. Precipitation is expected on 0 days (about 0.0 inches), against a normal of 0 days and 0.0 inches. The warmest day looks like 11 August (97.6°), the coolest 13 August (51.2°).

88.3°/54.6°

Average high / low

+2.5°

Above normal

0 / 0

Wet days / normal

0.0 in

Precipitation this month

Ten-day blocks vs climate normal

Period	Forecast high	Normal	Difference
9 August – 18 August	88.3°	84.5°	+2.2°
19 August – 28 August	88.2°	83.4°	+2.6°
29 August – 7 September	at normal	85°	—

August records over 66 years

103.6°4 August 1998All-time high

48.9°10 August 1960All-time low

Climate normals and records are computed from the nearest reference point — Boyes Hot Springs (13 mi).

Mon, 1092° / 56°

92 °

St. Helena, Monday, 10 August

Partly cloudy. High 92°, low 56°.

Pressure29.83 inHg

Wind5.2 mph S

Humidity17%

Visibility6.2 mi

Dew point43°

Tue, 1198° / 57°

98 °

St. Helena, Tuesday, 11 August

Clear. High 98°, low 57°.

Pressure29.88 inHg

Wind5.4 mph S

Humidity20%

Visibility6.2 mi

Dew point44°

Wed, 1290° / 55°

90 °

St. Helena, Wednesday, 12 August

Partly cloudy. High 90°, low 55°.

Pressure29.83 inHg

Wind6.5 mph S

Humidity28%

Visibility6.2 mi

Dew point47°

Thu, 1385° / 51°

85 °

St. Helena, Thursday, 13 August

Partly cloudy. High 85°, low 51°.

Pressure29.83 inHg

Wind11.3 mph SW

Humidity30%

Visibility—

Dew point47°

Fri, 1489° / 53°

89 °

St. Helena, Friday, 14 August

Clear. High 89°, low 53°.

Pressure29.88 inHg

Wind7.9 mph W

Humidity26%

Visibility—

Dew point46°

Sat, 1590° / 53°

90 °

St. Helena, Saturday, 15 August

Overcast. High 90°, low 53°.

Pressure29.94 inHg

Wind8.1 mph SW

Humidity22%

Visibility—

Dew point42°

Sun, 1688° / 55°

88 °

St. Helena, Sunday, 16 August

Overcast. High 88°, low 55°.

Pressure30.03 inHg

Wind9.4 mph W

Humidity29%

Visibility—

Dew point49°

Mon, 1778° / 53°

78 °

St. Helena, Monday, 17 August

Overcast. High 78°, low 53°.

Pressure30.06 inHg

Wind9.8 mph SW

Humidity36%

Visibility—

Dew point46°

Tue, 1882° / 53°

82 °

St. Helena, Tuesday, 18 August

Overcast. High 82°, low 53°.

Pressure29.97 inHg

Wind10.9 mph SW

Humidity43%

Visibility—

Dew point55°

Wed, 1988° / 59°

88 °

St. Helena, Wednesday, 19 August

Clear. High 88°, low 59°.

Pressure29.91 inHg

Wind10.1 mph SW

Humidity33%

Visibility—

Dew point53°

Thu, 2082° / 58°

82 °

St. Helena, Thursday, 20 August

Overcast. High 82°, low 58°.

Pressure29.94 inHg

Wind8.6 mph SW

Humidity42%

Visibility—

Dew point55°

Fri, 2187° / 54°

87 °

St. Helena, Friday, 21 August

Partly cloudy. High 87°, low 54°.

Pressure29.88 inHg

Wind9.9 mph SW

Humidity19%

Visibility—

Dew point37°

Sat, 2289° / 51°

89 °

St. Helena, Saturday, 22 August

Overcast. High 89°, low 51°.

Pressure29.91 inHg

Wind7.4 mph SW

Humidity20%

Visibility—

Dew point39°

Sun, 2391° / 54°

91 °

St. Helena, Sunday, 23 August

Clear. High 91°, low 54°.

Pressure29.88 inHg

Wind8.3 mph SW

Humidity20%

Visibility—

Dew point41°

Mon, 2492° / 52°

92 °

St. Helena, Monday, 24 August

Clear. High 92°, low 52°.

Pressure29.83 inHg

Wind9.1 mph SW

Humidity15%

Visibility—

Dew point34°

From day 17 onward the outlook is built from 60-year climate statistics

Tue, 2583° / 57°

83 °

St. Helena, Tuesday, 25 August

Climate normal for this date — 60-year average.

Average high83°

Average low57°

Average precipitation0 in

Chance of precipitation0%

Record high100° (1988)

Record low52° (2021)

Wed, 2684° / 56°

84 °

St. Helena, Wednesday, 26 August

Climate normal for this date — 60-year average.

Average high84°

Average low56°

Average precipitation0 in

Chance of precipitation0%

Record high100° (1988)

Record low52° (1966)

Thu, 2785° / 57°

85 °

St. Helena, Thursday, 27 August

Climate normal for this date — 60-year average.

Average high85°

Average low57°

Average precipitation0 in

Chance of precipitation0%

Record high101° (2017)

Record low51° (2023)

Fri, 2886° / 58°

86 °

St. Helena, Friday, 28 August

Climate normal for this date — 60-year average.

Average high86°

Average low58°

Average precipitation0 in

Chance of precipitation0%

Record high102° (2021)

Record low53° (1985)

Sat, 2985° / 58°

85 °

St. Helena, Saturday, 29 August

Climate normal for this date — 60-year average.

Average high85°

Average low58°

Average precipitation0 in

Chance of precipitation2%

Record high99° (2009)

Record low50° (1980)

Sun, 3084° / 58°

84 °

St. Helena, Sunday, 30 August

Climate normal for this date — 60-year average.

Average high84°

Average low58°

Average precipitation0 in

Chance of precipitation2%

Record high99° (1996)

Record low52° (1960)

Mon, 3185° / 57°

0.01

85 °

St. Helena, Monday, 31 August

Climate normal for this date — 60-year average.

Average high85°

Average low57°

Average precipitation0.01 in

Chance of precipitation3%

Record high96° (2017)

Record low52° (1970)

Tue, 0185° / 57°

85 °

St. Helena, Tuesday, 1 September

Climate normal for this date — 60-year average.

Average high85°

Average low57°

Average precipitation0 in

Chance of precipitation2%

Record high107° (2017)

Record low51° (2021)

Wed, 0285° / 58°

85 °

St. Helena, Wednesday, 2 September

Climate normal for this date — 60-year average.

Average high85°

Average low58°

Average precipitation0 in

Chance of precipitation2%

Record high107° (2017)

Record low51° (1960)

Thu, 0385° / 57°

85 °

St. Helena, Thursday, 3 September

Climate normal for this date — 60-year average.

Average high85°

Average low57°

Average precipitation0 in

Chance of precipitation0%

Record high98° (2017)

Record low49° (2000)

Fri, 0485° / 57°

85 °

St. Helena, Friday, 4 September

Climate normal for this date — 60-year average.

Average high85°

Average low57°

Average precipitation0 in

Chance of precipitation0%

Record high101° (2022)

Record low50° (2000)

Sat, 0586° / 58°

86 °

St. Helena, Saturday, 5 September

Climate normal for this date — 60-year average.

Average high86°

Average low58°

Average precipitation0 in

Chance of precipitation0%

Record high109° (2022)

Record low52° (1965)

Sun, 0685° / 57°

85 °

St. Helena, Sunday, 6 September

Climate normal for this date — 60-year average.

Average high85°

Average low57°

Average precipitation0 in

Chance of precipitation0%

Record high112° (2022)

Record low52° (1980)

Mon, 0785° / 58°

85 °

St. Helena, Monday, 7 September

Climate normal for this date — 60-year average.

Average high85°

Average low58°

Average precipitation0 in

Chance of precipitation2%

Record high110° (2020)

Record low51° (2002)

About the monthly outlook

How accurate is a 30-day forecast?

The first 16 days come from weather models — reliable for the first 3–5 days and progressively less so after that. Days 17 through 30 for St. Helena, CA are built from the climate normal, the 60-year average, so they show typical weather for those dates rather than a specific forecast.

What does "above normal" mean?

We compare the forecast against the climate normal for those exact calendar days, computed from 60 years of observations. The deviation shows how much the coming month differs from a typical one.

Where do the 66-year records come from?

They are real temperature extremes recorded in St. Helena, CA since 1960: the highest and lowest reading for each calendar date, with the year it happened.

How often is it updated?

The forecast portion refreshes every hour; the climate portion is based on long-term data and stays stable.