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St. Helena, CA

59°F
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St. Helena

California

59°
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St. Helena, CA Weather
Today WinterCast Local {stormName} Tracker Hourly 10-Day Radar MinuteCast® Monthly Air Quality Health & Activities

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Today Hourly 10-Day Radar MinuteCast®

Monthly

Air Quality Health & Activities

September

January February March April May June July August September October November December

2026

2025 2026 2027

10-Day

S
M
T
W
T
F
S
30
Wall-to-wall sunshine
90°
56°
31
Mostly sunny and warm
92°
58°
1
Warm with plenty of sunshine
92°
58°
2
Warm with sunshine
93°
57°
3
Mostly sunny and warm
92°
56°
4
Partly sunny and warm
92°
58°
5
Mostly sunny
91°
57°
6
Mostly sunny and warm
91°
58°
7
Warm with plenty of sun
92°
58°
8
Mostly sunny and warm
92°
55°
9
Sunshine and some clouds
89°
56°
10
Mostly sunny
85°
57°
11
Sunny
90°
58°
12
Mostly sunny
86°
56°
13
Mostly sunny
85°
55°
14
Mostly cloudy, a little rain
82°
52°
15
A couple of showers
84°
52°
16
Sunny
89°
52°
17
Partly sunny
89°
56°
18
Hist. Avg.
86°
54°
19
Hist. Avg.
86°
54°
20
Hist. Avg.
86°
53°
21
Hist. Avg.
86°
53°
22
Hist. Avg.
86°
53°
23
Hist. Avg.
85°
53°
24
Hist. Avg.
85°
53°
25
Hist. Avg.
85°
53°
26
Hist. Avg.
85°
53°
27
Hist. Avg.
84°
52°
28
Hist. Avg.
84°
52°
29
Hist. Avg.
84°
52°
30
Hist. Avg.
84°
52°
1
Hist. Avg.
83°
52°
2
Hist. Avg.
83°
52°
3
Hist. Avg.
83°
52°

Temperature Graph

°F
100° 90° 80° 70° 60° Sep
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 *18 *19 *20 *21 *22 *23 *24 *25 *26 *27 *28 *29 *30
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable

September Weather in St. Helena

St. Helena's September 2026 forecast shows daily high temperatures ranging from 82° to 93°, with overnight lows between 52° and 58°. The average high for September is 89° with an average low of 56°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in St. Helena. See also: October | November | December.

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Weather Near St. Helena:

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