Monthly outlook for Roundup, MT: average high 58.5°, average low 38.1°. That is 0.8° below the climate normal for October. Precipitation is expected on 3 days (about 0.6 inches), against a normal of 3 days and 0.7 inches. The warmest day looks like 9 October (83.1°), the coolest 13 October (25.1°).
58.5°/38.1°
Average high / low
−0.8°
Below normal
3 / 3
Wet days / normal
0.6 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
7 October – 16 October
57.8°
60.3°
-1.4°
17 October – 26 October
59.6°
58°
+0.9°
27 October – 5 November
at normal
51.4°
—
October records over 66 years
90.3°1 October 2011All-time high
-15.5°30 October 1991All-time low
Climate normals and records are computed from the nearest reference point — Klein (4 mi).
Thu, 0880° / 42°0
80 °
Roundup, Thursday, 8 October
Clear. High 80°, low 42°.
Pressure29.94 inHg
Wind4.9 mph S
Humidity21%
Visibility6.2 mi
Dew point31°
Fri, 0983° / 47°0
83 °
Roundup, Friday, 9 October
Partly cloudy. High 83°, low 47°.
Pressure29.56 inHg
Wind11.5 mph SW
Humidity20%
Visibility6.2 mi
Dew point33°
Sat, 1063° / 37°0
63 °
Roundup, Saturday, 10 October
Light rain. High 63°, low 37°.
Pressure29.68 inHg
Wind13.3 mph NE
Humidity57%
Visibility6.2 mi
Dew point41°
Sun, 1136° / 32°0.24
36 °
Roundup, Sunday, 11 October
Snow. High 36°, low 32°.
Pressure30.21 inHg
Wind11.1 mph NE
Humidity88%
Visibility1.1 mi
Dew point27°
Mon, 1238° / 30°0.22
38 °
Roundup, Monday, 12 October
Snow. High 38°, low 30°.
Pressure30.27 inHg
Wind8.1 mph SW
Humidity85%
Visibility—
Dew point30°
Tue, 1357° / 25°0
57 °
Roundup, Tuesday, 13 October
Clear. High 57°, low 25°.
Pressure30.12 inHg
Wind11.3 mph W
Humidity55%
Visibility—
Dew point29°
Wed, 1458° / 40°0.17
58 °
Roundup, Wednesday, 14 October
Rain. High 58°, low 40°.
Pressure29.56 inHg
Wind19.9 mph N
Humidity38%
Visibility—
Dew point31°
Thu, 1540° / 34°0
40 °
Roundup, Thursday, 15 October
Overcast. High 40°, low 34°.
Pressure30.27 inHg
Wind24.5 mph N
Humidity51%
Visibility—
Dew point22°
Fri, 1648° / 29°0
48 °
Roundup, Friday, 16 October
Clear. High 48°, low 29°.
Pressure30.47 inHg
Wind9.1 mph N
Humidity36%
Visibility—
Dew point15°
Sat, 1762° / 35°0
62 °
Roundup, Saturday, 17 October
Clear. High 62°, low 35°.
Pressure30.03 inHg
Wind13.8 mph SW
Humidity23%
Visibility—
Dew point16°
Sun, 1867° / 42°0
67 °
Roundup, Sunday, 18 October
Clear. High 67°, low 42°.
Pressure29.94 inHg
Wind16.3 mph SW
Humidity28%
Visibility—
Dew point24°
Mon, 1952° / 43°0
52 °
Roundup, Monday, 19 October
Overcast. High 52°, low 43°.
Pressure30.30 inHg
Wind12.3 mph N
Humidity46%
Visibility—
Dew point28°
Tue, 2064° / 40°0
64 °
Roundup, Tuesday, 20 October
Clear. High 64°, low 40°.
Pressure30.03 inHg
Wind17.7 mph SW
Humidity42%
Visibility—
Dew point31°
Wed, 2164° / 47°0
64 °
Roundup, Wednesday, 21 October
Overcast. High 64°, low 47°.
Pressure29.62 inHg
Wind34.3 mph NW
Humidity29%
Visibility—
Dew point26°
Thu, 2248° / 41°0
48 °
Roundup, Thursday, 22 October
Overcast. High 48°, low 41°.
Pressure29.77 inHg
Wind23.8 mph NW
Humidity32%
Visibility—
Dew point19°
From day 17 onward the outlook is built from 60-year climate statistics
Fri, 2357° / 36°0.03
57 °
Roundup, Friday, 23 October
Climate normal for this date — 60-year average.
Average high57°
Average low36°
Average precipitation0.03 in
Chance of precipitation17%
Record high73° (1973)
Record low7° (2020)
Sat, 2457° / 35°0.03
57 °
Roundup, Saturday, 24 October
Climate normal for this date — 60-year average.
Average high57°
Average low35°
Average precipitation0.03 in
Chance of precipitation18%
Record high76° (1992)
Record low7° (1975)
Sun, 2556° / 36°0.03
56 °
Roundup, Sunday, 25 October
Climate normal for this date — 60-year average.
Average high56°
Average low36°
Average precipitation0.03 in
Chance of precipitation20%
Record high75° (2017)
Record low-4° (2020)
Mon, 2655° / 36°0.04
55 °
Roundup, Monday, 26 October
Climate normal for this date — 60-year average.
Average high55°
Average low36°
Average precipitation0.04 in
Chance of precipitation17%
Record high73° (1960)
Record low-1° (2020)
Tue, 2754° / 33°0.03
54 °
Roundup, Tuesday, 27 October
Climate normal for this date — 60-year average.
Average high54°
Average low33°
Average precipitation0.03 in
Chance of precipitation15%
Record high71° (2024)
Record low1° (2023)
Wed, 2853° / 33°0.04
53 °
Roundup, Wednesday, 28 October
Climate normal for this date — 60-year average.
Average high53°
Average low33°
Average precipitation0.04 in
Chance of precipitation22%
Record high74° (1990)
Record low2° (2023)
Thu, 2951° / 33°0.03
51 °
Roundup, Thursday, 29 October
Climate normal for this date — 60-year average.
Average high51°
Average low33°
Average precipitation0.03 in
Chance of precipitation23%
Record high73° (1987)
Record low-4° (1991)
Fri, 3051° / 31°0.02
51 °
Roundup, Friday, 30 October
Climate normal for this date — 60-year average.
Average high51°
Average low31°
Average precipitation0.02 in
Chance of precipitation15%
Record high71° (1990)
Record low-16° (1991)
Sat, 3151° / 32°0.05
51 °
Roundup, Saturday, 31 October
Climate normal for this date — 60-year average.
Average high51°
Average low32°
Average precipitation0.05 in
Chance of precipitation15%
Record high73° (1990)
Record low8° (1984)
Sun, 0151° / 32°0.02
51 °
Roundup, Sunday, 1 November
Climate normal for this date — 60-year average.
Average high51°
Average low32°
Average precipitation0.02 in
Chance of precipitation13%
Record high70° (1981)
Record low-1° (1991)
Mon, 0250° / 31°0.01
50 °
Roundup, Monday, 2 November
Climate normal for this date — 60-year average.
Average high50°
Average low31°
Average precipitation0.01 in
Chance of precipitation8%
Record high69° (1965)
Record low-16° (1991)
Tue, 0351° / 31°0.03
51 °
Roundup, Tuesday, 3 November
Climate normal for this date — 60-year average.
Average high51°
Average low31°
Average precipitation0.03 in
Chance of precipitation17%
Record high69° (1962)
Record low-12° (1991)
Wed, 0451° / 32°0.03
51 °
Roundup, Wednesday, 4 November
Climate normal for this date — 60-year average.
Average high51°
Average low32°
Average precipitation0.03 in
Chance of precipitation17%
Record high71° (1976)
Record low6° (2003)
Thu, 0550° / 32°0.05
50 °
Roundup, Thursday, 5 November
Climate normal for this date — 60-year average.
Average high50°
Average low32°
Average precipitation0.05 in
Chance of precipitation25%
Record high69° (2010)
Record low0° (2003)
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 Roundup, MT 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 Roundup, MT 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.