Monthly outlook for Fullerton, CA: average high 83.4°, average low 68.8°. That is 2.5° above the climate normal for October. Precipitation is expected on 2 days (about 0.9 inches), against a normal of 1 days and 0.3 inches. The warmest day looks like 17 October (96°), the coolest 13 October (53.3°).
83.4°/68.8°
Average high / low
+2.5°
Above normal
2 / 1
Wet days / normal
0.9 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
10 October – 19 October
81.5°
79.5°
+1.1°
20 October – 29 October
86.6°
77.3°
+5.1°
30 October – 8 November
at normal
74.7°
—
October records over 66 years
103.6°4 October 1987All-time high
35.6°30 October 1971All-time low
Sun, 1171° / 62°0.42
71 °
Fullerton, Sunday, 11 October
Rain. High 71°, low 62°.
Pressure29.68 inHg
Wind7.9 mph S
Humidity90%
Visibility3.5 mi
Dew point63°
Mon, 1265° / 54°0.44
65 °
Fullerton, Monday, 12 October
Rain. High 65°, low 54°.
Pressure29.88 inHg
Wind5.6 mph S
Humidity70%
Visibility5.2 mi
Dew point54°
Tue, 1369° / 53°0
69 °
Fullerton, Tuesday, 13 October
Mostly clear. High 69°, low 53°.
Pressure30.00 inHg
Wind1.2 mph SW
Humidity58%
Visibility6.2 mi
Dew point50°
Wed, 1474° / 54°0
74 °
Fullerton, Wednesday, 14 October
Clear. High 74°, low 54°.
Pressure30.03 inHg
Wind5 mph NE
Humidity58%
Visibility—
Dew point51°
Thu, 1582° / 57°0
82 °
Fullerton, Thursday, 15 October
Clear. High 82°, low 57°.
Pressure30.03 inHg
Wind5.4 mph NE
Humidity43%
Visibility—
Dew point49°
Fri, 1693° / 75°0
93 °
Fullerton, Friday, 16 October
Clear. High 93°, low 75°.
Pressure29.94 inHg
Wind9.5 mph W
Humidity14%
Visibility—
Dew point30°
Sat, 1796° / 78°0
96 °
Fullerton, Saturday, 17 October
Clear. High 96°, low 78°.
Pressure29.91 inHg
Wind6.1 mph W
Humidity8%
Visibility—
Dew point19°
Sun, 1893° / 81°0
93 °
Fullerton, Sunday, 18 October
Clear. High 93°, low 81°.
Pressure29.91 inHg
Wind8.5 mph SW
Humidity12%
Visibility—
Dew point29°
Mon, 1987° / 77°0
87 °
Fullerton, Monday, 19 October
Clear. High 87°, low 77°.
Pressure29.91 inHg
Wind9.1 mph SW
Humidity28%
Visibility—
Dew point47°
Tue, 2083° / 73°0
83 °
Fullerton, Tuesday, 20 October
Clear. High 83°, low 73°.
Pressure29.88 inHg
Wind9 mph SW
Humidity41%
Visibility—
Dew point53°
Wed, 2179° / 69°0
79 °
Fullerton, Wednesday, 21 October
Clear. High 79°, low 69°.
Pressure29.91 inHg
Wind8.5 mph SW
Humidity57%
Visibility—
Dew point57°
Thu, 2287° / 70°0
87 °
Fullerton, Thursday, 22 October
Mostly clear. High 87°, low 70°.
Pressure29.94 inHg
Wind8 mph W
Humidity29%
Visibility—
Dew point44°
Fri, 2389° / 75°0
89 °
Fullerton, Friday, 23 October
Mostly clear. High 89°, low 75°.
Pressure29.91 inHg
Wind8.3 mph SW
Humidity15%
Visibility—
Dew point30°
Sat, 2494° / 77°0
94 °
Fullerton, Saturday, 24 October
Mostly clear. High 94°, low 77°.
Pressure29.83 inHg
Wind9.6 mph W
Humidity9%
Visibility—
Dew point21°
Sun, 2586° / 75°0
86 °
Fullerton, Sunday, 25 October
Mostly clear. High 86°, low 75°.
Pressure29.74 inHg
Wind10.1 mph S
Humidity21%
Visibility—
Dew point38°
From day 17 onward the outlook is built from 60-year climate statistics
Mon, 2677° / 55°0.01
77 °
Fullerton, Monday, 26 October
Climate normal for this date — 60-year average.
Average high77°
Average low55°
Average precipitation0.01 in
Chance of precipitation5%
Record high92° (1965)
Record low45° (1989)
Tue, 2776° / 55°0.05
76 °
Fullerton, Tuesday, 27 October
Climate normal for this date — 60-year average.
Average high76°
Average low55°
Average precipitation0.05 in
Chance of precipitation10%
Record high93° (1965)
Record low44° (1996)
Wed, 2876° / 54°0.01
76 °
Fullerton, Wednesday, 28 October
Climate normal for this date — 60-year average.
Average high76°
Average low54°
Average precipitation0.01 in
Chance of precipitation12%
Record high93° (1965)
Record low43° (1970)
Thu, 2975° / 54°0
75 °
Fullerton, Thursday, 29 October
Climate normal for this date — 60-year average.
Average high75°
Average low54°
Average precipitation0 in
Chance of precipitation2%
Record high92° (2025)
Record low36° (1971)
Fri, 3075° / 54°0.05
75 °
Fullerton, Friday, 30 October
Climate normal for this date — 60-year average.
Average high75°
Average low54°
Average precipitation0.05 in
Chance of precipitation15%
Record high92° (1962)
Record low36° (1971)
Sat, 3175° / 53°0.02
75 °
Fullerton, Saturday, 31 October
Climate normal for this date — 60-year average.
Average high75°
Average low53°
Average precipitation0.02 in
Chance of precipitation5%
Record high91° (1962)
Record low40° (1971)
Sun, 0176° / 53°0.03
76 °
Fullerton, Sunday, 1 November
Climate normal for this date — 60-year average.
Average high76°
Average low53°
Average precipitation0.03 in
Chance of precipitation10%
Record high94° (1997)
Record low41° (1971)
Mon, 0276° / 53°0.01
76 °
Fullerton, Monday, 2 November
Climate normal for this date — 60-year average.
Average high76°
Average low53°
Average precipitation0.01 in
Chance of precipitation12%
Record high94° (1997)
Record low43° (1971)
Tue, 0376° / 52°0
76 °
Fullerton, Tuesday, 3 November
Climate normal for this date — 60-year average.
Average high76°
Average low52°
Average precipitation0 in
Chance of precipitation3%
Record high94° (2010)
Record low43° (1990)
Wed, 0475° / 52°0.02
75 °
Fullerton, Wednesday, 4 November
Climate normal for this date — 60-year average.
Average high75°
Average low52°
Average precipitation0.02 in
Chance of precipitation5%
Record high94° (1976)
Record low39° (1994)
Thu, 0574° / 52°0.01
74 °
Fullerton, Thursday, 5 November
Climate normal for this date — 60-year average.
Average high74°
Average low52°
Average precipitation0.01 in
Chance of precipitation3%
Record high97° (2020)
Record low43° (2011)
Fri, 0673° / 53°0.02
73 °
Fullerton, Friday, 6 November
Climate normal for this date — 60-year average.
Average high73°
Average low53°
Average precipitation0.02 in
Chance of precipitation8%
Record high92° (2006)
Record low44° (2011)
Sat, 0772° / 53°0.07
72 °
Fullerton, Saturday, 7 November
Climate normal for this date — 60-year average.
Average high72°
Average low53°
Average precipitation0.07 in
Chance of precipitation8%
Record high91° (2006)
Record low39° (2011)
Sun, 0873° / 53°0.09
73 °
Fullerton, Sunday, 8 November
Climate normal for this date — 60-year average.
Average high73°
Average low53°
Average precipitation0.09 in
Chance of precipitation18%
Record high90° (2016)
Record low40° (2011)
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 Fullerton, 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 Fullerton, 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.