Monthly outlook for Altona, CO: average high 83.1°, average low 60.7°. That is 0.9° above the climate normal for August. Precipitation is expected on 10 days (about 2.6 inches), against a normal of 8 days and 1.4 inches. The warmest day looks like 8 August (92.8°), the coolest 16 August (57°).
83.1°/60.7°
Average high / low
+0.9°
Above normal
10 / 8
Wet days / normal
2.6 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
8 August – 17 August
83.8°
81.5°
+1.3°
18 August – 27 August
82°
81.3°
+0.4°
28 August – 6 September
at normal
80.2°
—
August records over 66 years
97.9°7 August 2025All-time high
40.5°28 August 2004All-time low
Climate normals and records are computed from the nearest reference point — Boulder (7 mi).
Sun, 0990° / 61°0.08
90 °
Altona, Sunday, 9 August
Light rain. High 90°, low 61°.
Pressure29.83 inHg
Wind1.9 mph W
Humidity13%
Visibility6.2 mi
Dew point32°
Mon, 1089° / 57°0.1
89 °
Altona, Monday, 10 August
Light rain. High 89°, low 57°.
Pressure29.85 inHg
Wind10.2 mph E
Humidity20%
Visibility6.2 mi
Dew point42°
Tue, 1190° / 64°0
90 °
Altona, Tuesday, 11 August
Overcast. High 90°, low 64°.
Pressure29.85 inHg
Wind11.7 mph E
Humidity19%
Visibility6.2 mi
Dew point39°
Wed, 1289° / 65°0.04
89 °
Altona, Wednesday, 12 August
Light rain. High 89°, low 65°.
Pressure29.83 inHg
Wind7.4 mph E
Humidity20%
Visibility6.2 mi
Dew point40°
Thu, 1379° / 61°0.56
79 °
Altona, Thursday, 13 August
Rain. High 79°, low 61°.
Pressure29.83 inHg
Wind13.6 mph NW
Humidity38%
Visibility—
Dew point49°
Fri, 1476° / 60°0.14
76 °
Altona, Friday, 14 August
Light rain. High 76°, low 60°.
Pressure30.00 inHg
Wind7.6 mph E
Humidity75%
Visibility—
Dew point56°
Sat, 1572° / 60°0.51
72 °
Altona, Saturday, 15 August
Rain. High 72°, low 60°.
Pressure30.15 inHg
Wind8.5 mph E
Humidity64%
Visibility—
Dew point57°
Sun, 1677° / 57°0.06
77 °
Altona, Sunday, 16 August
Light rain. High 77°, low 57°.
Pressure30.06 inHg
Wind6.2 mph SW
Humidity43%
Visibility—
Dew point50°
Mon, 1783° / 61°0.03
83 °
Altona, Monday, 17 August
Light rain. High 83°, low 61°.
Pressure30.03 inHg
Wind10.5 mph W
Humidity25%
Visibility—
Dew point41°
Tue, 1890° / 62°0
90 °
Altona, Tuesday, 18 August
Clear. High 90°, low 62°.
Pressure29.97 inHg
Wind9.7 mph W
Humidity23%
Visibility—
Dew point42°
Wed, 1974° / 61°0.72
74 °
Altona, Wednesday, 19 August
Rain. High 74°, low 61°.
Pressure30.03 inHg
Wind9.4 mph NW
Humidity46%
Visibility—
Dew point50°
Thu, 2074° / 61°0.11
74 °
Altona, Thursday, 20 August
Light rain. High 74°, low 61°.
Pressure30.00 inHg
Wind12.5 mph NE
Humidity56%
Visibility—
Dew point53°
Fri, 2182° / 59°0.21
82 °
Altona, Friday, 21 August
Rain. High 82°, low 59°.
Pressure29.77 inHg
Wind16.6 mph W
Humidity29%
Visibility—
Dew point44°
Sat, 2286° / 59°0
86 °
Altona, Saturday, 22 August
Partly cloudy. High 86°, low 59°.
Pressure29.88 inHg
Wind9.1 mph E
Humidity21%
Visibility—
Dew point36°
Sun, 2386° / 60°0
86 °
Altona, Sunday, 23 August
Partly cloudy. High 86°, low 60°.
Pressure29.88 inHg
Wind9.3 mph W
Humidity26%
Visibility—
Dew point42°
From day 17 onward the outlook is built from 60-year climate statistics
Mon, 2481° / 56°0.09
81 °
Altona, Monday, 24 August
Climate normal for this date — 60-year average.
Average high81°
Average low56°
Average precipitation0.09 in
Chance of precipitation37%
Record high93° (2020)
Record low44° (1968)
Tue, 2581° / 56°0.07
81 °
Altona, Tuesday, 25 August
Climate normal for this date — 60-year average.
Average high81°
Average low56°
Average precipitation0.07 in
Chance of precipitation50%
Record high94° (2019)
Record low47° (1972)
Wed, 2681° / 56°0.08
81 °
Altona, Wednesday, 26 August
Climate normal for this date — 60-year average.
Average high81°
Average low56°
Average precipitation0.08 in
Chance of precipitation48%
Record high91° (1994)
Record low48° (1992)
Thu, 2781° / 56°0.08
81 °
Altona, Thursday, 27 August
Climate normal for this date — 60-year average.
Average high81°
Average low56°
Average precipitation0.08 in
Chance of precipitation42%
Record high92° (2012)
Record low43° (1992)
Fri, 2881° / 55°0.07
81 °
Altona, Friday, 28 August
Climate normal for this date — 60-year average.
Average high81°
Average low55°
Average precipitation0.07 in
Chance of precipitation57%
Record high90° (2013)
Record low40° (2004)
Sat, 2981° / 55°0.06
81 °
Altona, Saturday, 29 August
Climate normal for this date — 60-year average.
Average high81°
Average low55°
Average precipitation0.06 in
Chance of precipitation40%
Record high93° (2012)
Record low46° (2004)
Sun, 3081° / 55°0.08
81 °
Altona, Sunday, 30 August
Climate normal for this date — 60-year average.
Average high81°
Average low55°
Average precipitation0.08 in
Chance of precipitation40%
Record high91° (2005)
Record low44° (1964)
Mon, 3180° / 55°0.07
80 °
Altona, Monday, 31 August
Climate normal for this date — 60-year average.
Average high80°
Average low55°
Average precipitation0.07 in
Chance of precipitation42%
Record high93° (2011)
Record low44° (1968)
Tue, 0180° / 54°0.08
80 °
Altona, Tuesday, 1 September
Climate normal for this date — 60-year average.
Average high80°
Average low54°
Average precipitation0.08 in
Chance of precipitation37%
Record high94° (2019)
Record low42° (1965)
Wed, 0280° / 53°0.06
80 °
Altona, Wednesday, 2 September
Climate normal for this date — 60-year average.
Average high80°
Average low53°
Average precipitation0.06 in
Chance of precipitation38%
Record high95° (2019)
Record low41° (1974)
Thu, 0380° / 53°0.05
80 °
Altona, Thursday, 3 September
Climate normal for this date — 60-year average.
Average high80°
Average low53°
Average precipitation0.05 in
Chance of precipitation30%
Record high92° (2017)
Record low37° (1961)
Fri, 0480° / 53°0.05
80 °
Altona, Friday, 4 September
Climate normal for this date — 60-year average.
Average high80°
Average low53°
Average precipitation0.05 in
Chance of precipitation33%
Record high92° (1960)
Record low41° (1961)
Sat, 0580° / 53°0.05
80 °
Altona, Saturday, 5 September
Climate normal for this date — 60-year average.
Average high80°
Average low53°
Average precipitation0.05 in
Chance of precipitation25%
Record high94° (2020)
Record low44° (1962)
Sun, 0679° / 53°0.06
79 °
Altona, Sunday, 6 September
Climate normal for this date — 60-year average.
Average high79°
Average low53°
Average precipitation0.06 in
Chance of precipitation40%
Record high95° (2020)
Record low43° (1968)
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 Altona, CO 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 Altona, CO 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.