Monthly outlook for Diamond Bar, CA: average high 73.5°, average low 61.2°. That is 0.5° below the climate normal for October. Precipitation is expected on 6 days (about 2.9 inches), against a normal of 2 days and 0.5 inches. The warmest day looks like 26 October (82.2°), the coolest 27 October (57.3°).
73.5°/61.2°
Average high / low
−0.5°
Below normal
6 / 2
Wet days / normal
2.9 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
26 October – 4 November
73.8°
75.6°
-1°
5 November – 14 November
72.9°
72.1°
+0.4°
15 November – 24 November
at normal
69.2°
—
October records over 66 years
104°1 October 2020All-time high
34.2°29 October 1971All-time low
Climate normals and records are computed from the nearest reference point — Pomona (5 mi).
Tue, 2780° / 57°0
80 °
Diamond Bar, Tuesday, 27 October
Clear. High 80°, low 57°.
Pressure30.00 inHg
Wind0.2 mph W
Humidity39%
Visibility6.2 mi
Dew point49°
Wed, 2880° / 58°0
80 °
Diamond Bar, Wednesday, 28 October
Clear. High 80°, low 58°.
Pressure29.97 inHg
Wind0.3 mph NE
Humidity38%
Visibility6.2 mi
Dew point48°
Thu, 2978° / 59°0
78 °
Diamond Bar, Thursday, 29 October
Overcast. High 78°, low 59°.
Pressure29.91 inHg
Wind1.3 mph SW
Humidity46%
Visibility6.2 mi
Dew point53°
Fri, 3073° / 64°0.09
73 °
Diamond Bar, Friday, 30 October
Light rain. High 73°, low 64°.
Pressure29.94 inHg
Wind4.4 mph SW
Humidity61%
Visibility—
Dew point55°
Sat, 3169° / 58°0.57
69 °
Diamond Bar, Saturday, 31 October
Rain. High 69°, low 58°.
Pressure29.94 inHg
Wind4.7 mph SW
Humidity63%
Visibility—
Dew point54°
Sun, 0165° / 60°1.24
65 °
Diamond Bar, Sunday, 1 November
Rain. High 65°, low 60°.
Pressure29.94 inHg
Wind13.2 mph E
Humidity81%
Visibility—
Dew point54°
Mon, 0273° / 66°0.05
73 °
Diamond Bar, Monday, 2 November
Light rain. High 73°, low 66°.
Pressure29.97 inHg
Wind5.3 mph E
Humidity63%
Visibility—
Dew point54°
Tue, 0370° / 64°0.33
70 °
Diamond Bar, Tuesday, 3 November
Light rain. High 70°, low 64°.
Pressure30.06 inHg
Wind9.9 mph SW
Humidity77%
Visibility—
Dew point60°
Wed, 0469° / 62°0
69 °
Diamond Bar, Wednesday, 4 November
Overcast. High 69°, low 62°.
Pressure30.06 inHg
Wind5 mph SW
Humidity66%
Visibility—
Dew point53°
Thu, 0572° / 62°0
72 °
Diamond Bar, Thursday, 5 November
Partly cloudy. High 72°, low 62°.
Pressure30.06 inHg
Wind8.4 mph SW
Humidity62%
Visibility—
Dew point53°
Fri, 0673° / 62°0
73 °
Diamond Bar, Friday, 6 November
Overcast. High 73°, low 62°.
Pressure30.03 inHg
Wind7 mph SW
Humidity50%
Visibility—
Dew point47°
Sat, 0769° / 62°0.64
69 °
Diamond Bar, Saturday, 7 November
Rain. High 69°, low 62°.
Pressure29.91 inHg
Wind14.4 mph S
Humidity51%
Visibility—
Dew point47°
Sun, 0870° / 60°0
70 °
Diamond Bar, Sunday, 8 November
Clear. High 70°, low 60°.
Pressure29.94 inHg
Wind6.1 mph S
Humidity53%
Visibility—
Dew point47°
Mon, 0976° / 62°0
76 °
Diamond Bar, Monday, 9 November
Clear. High 76°, low 62°.
Pressure30.00 inHg
Wind7.9 mph SW
Humidity22%
Visibility—
Dew point28°
Tue, 1078° / 64°0
78 °
Diamond Bar, Tuesday, 10 November
Clear. High 78°, low 64°.
Pressure30.00 inHg
Wind7.5 mph SW
Humidity15%
Visibility—
Dew point21°
From day 17 onward the outlook is built from 60-year climate statistics
Wed, 1171° / 50°0.06
71 °
Diamond Bar, Wednesday, 11 November
Climate normal for this date — 60-year average.
Average high71°
Average low50°
Average precipitation0.06 in
Chance of precipitation13%
Record high90° (2021)
Record low37° (1982)
Thu, 1272° / 50°0.04
72 °
Diamond Bar, Thursday, 12 November
Climate normal for this date — 60-year average.
Average high72°
Average low50°
Average precipitation0.04 in
Chance of precipitation13%
Record high92° (2021)
Record low34° (1978)
Fri, 1372° / 50°0.04
72 °
Diamond Bar, Friday, 13 November
Climate normal for this date — 60-year average.
Average high72°
Average low50°
Average precipitation0.04 in
Chance of precipitation10%
Record high91° (2021)
Record low34° (1985)
Sat, 1472° / 50°0.04
72 °
Diamond Bar, Saturday, 14 November
Climate normal for this date — 60-year average.
Average high72°
Average low50°
Average precipitation0.04 in
Chance of precipitation7%
Record high91° (2021)
Record low35° (2000)
Sun, 1571° / 49°0.07
71 °
Diamond Bar, Sunday, 15 November
Climate normal for this date — 60-year average.
Average high71°
Average low49°
Average precipitation0.07 in
Chance of precipitation10%
Record high86° (2021)
Record low35° (1964)
Mon, 1670° / 49°0.05
70 °
Diamond Bar, Monday, 16 November
Climate normal for this date — 60-year average.
Average high70°
Average low49°
Average precipitation0.05 in
Chance of precipitation10%
Record high90° (2020)
Record low34° (1964)
Tue, 1769° / 49°0.04
69 °
Diamond Bar, Tuesday, 17 November
Climate normal for this date — 60-year average.
Average high69°
Average low49°
Average precipitation0.04 in
Chance of precipitation12%
Record high88° (2019)
Record low37° (1994)
Wed, 1869° / 49°0.06
69 °
Diamond Bar, Wednesday, 18 November
Climate normal for this date — 60-year average.
Average high69°
Average low49°
Average precipitation0.06 in
Chance of precipitation18%
Record high89° (2019)
Record low32° (1964)
Thu, 1970° / 48°0.04
70 °
Diamond Bar, Thursday, 19 November
Climate normal for this date — 60-year average.
Average high70°
Average low48°
Average precipitation0.04 in
Chance of precipitation7%
Record high86° (2006)
Record low25° (1964)
Fri, 2069° / 48°0.06
69 °
Diamond Bar, Friday, 20 November
Climate normal for this date — 60-year average.
Average high69°
Average low48°
Average precipitation0.06 in
Chance of precipitation13%
Record high85° (2006)
Record low33° (1994)
Sat, 2168° / 48°0.1
68 °
Diamond Bar, Saturday, 21 November
Climate normal for this date — 60-year average.
Average high68°
Average low48°
Average precipitation0.1 in
Chance of precipitation20%
Record high86° (2017)
Record low36° (1994)
Sun, 2268° / 47°0.06
68 °
Diamond Bar, Sunday, 22 November
Climate normal for this date — 60-year average.
Average high68°
Average low47°
Average precipitation0.06 in
Chance of precipitation12%
Record high91° (2017)
Record low36° (1983)
Mon, 2369° / 47°0.01
69 °
Diamond Bar, Monday, 23 November
Climate normal for this date — 60-year average.
Average high69°
Average low47°
Average precipitation0.01 in
Chance of precipitation5%
Record high92° (2017)
Record low38° (2003)
Tue, 2469° / 47°0.04
69 °
Diamond Bar, Tuesday, 24 November
Climate normal for this date — 60-year average.
Average high69°
Average low47°
Average precipitation0.04 in
Chance of precipitation13%
Record high86° (2017)
Record low39° (1966)
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 Diamond Bar, 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 Diamond Bar, 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.