Monthly outlook for Portal, MT: average high 53.2°, average low 33°. That is 1.9° above the climate normal for October. Precipitation is expected on 3 days (about 1.1 inches), against a normal of 4 days and 0.7 inches. The warmest day looks like 20 October (60.5°), the coolest 24 October (22.8°).
53.2°/33°
Average high / low
+1.9°
Above normal
3 / 4
Wet days / normal
1.1 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
19 October – 28 October
53.4°
52.1°
+0.7°
29 October – 7 November
52.8°
45.5°
+4°
8 November – 17 November
at normal
41.4°
—
October records over 66 years
83.5°1 October 2011All-time high
-11.2°28 October 2023All-time low
Climate normals and records are computed from the nearest reference point — Jefferson City (5 mi).
Tue, 2060° / 34°0
60 °
Portal, Tuesday, 20 October
Overcast. High 60°, low 34°.
Pressure30.09 inHg
Wind3.2 mph NE
Humidity47%
Visibility6.2 mi
Dew point33°
Wed, 2160° / 33°0
60 °
Portal, Wednesday, 21 October
Clear. High 60°, low 33°.
Pressure30.03 inHg
Wind6 mph S
Humidity47%
Visibility6.2 mi
Dew point37°
Thu, 2260° / 38°0.01
60 °
Portal, Thursday, 22 October
Light rain. High 60°, low 38°.
Pressure29.85 inHg
Wind7 mph S
Humidity52%
Visibility6.2 mi
Dew point40°
Fri, 2343° / 33°0.83
43 °
Portal, Friday, 23 October
Rain. High 43°, low 33°.
Pressure29.77 inHg
Wind8.8 mph NW
Humidity95%
Visibility1.1 mi
Dew point37°
Sat, 2444° / 23°0
44 °
Portal, Saturday, 24 October
Clear. High 44°, low 23°.
Pressure30.15 inHg
Wind6.4 mph S
Humidity67%
Visibility—
Dew point26°
Sun, 2554° / 28°0
54 °
Portal, Sunday, 25 October
Overcast. High 54°, low 28°.
Pressure30.18 inHg
Wind5.7 mph SW
Humidity39%
Visibility—
Dew point22°
Mon, 2656° / 28°0
56 °
Portal, Monday, 26 October
Overcast. High 56°, low 28°.
Pressure30.12 inHg
Wind7.7 mph N
Humidity24%
Visibility—
Dew point17°
Tue, 2741° / 23°0
41 °
Portal, Tuesday, 27 October
Overcast. High 41°, low 23°.
Pressure30.47 inHg
Wind6.1 mph N
Humidity61%
Visibility—
Dew point21°
Wed, 2856° / 28°0
56 °
Portal, Wednesday, 28 October
Clear. High 56°, low 28°.
Pressure30.09 inHg
Wind5.3 mph SW
Humidity34%
Visibility—
Dew point21°
Thu, 2958° / 40°0
58 °
Portal, Thursday, 29 October
Overcast. High 58°, low 40°.
Pressure29.91 inHg
Wind6.7 mph SW
Humidity22%
Visibility—
Dew point15°
Fri, 3058° / 43°0
58 °
Portal, Friday, 30 October
Overcast. High 58°, low 43°.
Pressure29.88 inHg
Wind12.3 mph W
Humidity20%
Visibility—
Dew point15°
Sat, 3152° / 42°0.04
52 °
Portal, Saturday, 31 October
Light rain. High 52°, low 42°.
Pressure29.94 inHg
Wind7.9 mph SW
Humidity42%
Visibility—
Dew point28°
Sun, 0152° / 37°0.02
52 °
Portal, Sunday, 1 November
Light rain. High 52°, low 37°.
Pressure30.15 inHg
Wind7 mph SW
Humidity55%
Visibility—
Dew point31°
Mon, 0251° / 37°0
51 °
Portal, Monday, 2 November
Overcast. High 51°, low 37°.
Pressure29.85 inHg
Wind6.1 mph SE
Humidity55%
Visibility—
Dew point32°
Tue, 0345° / 32°0.16
45 °
Portal, Tuesday, 3 November
Light rain. High 45°, low 32°.
Pressure29.65 inHg
Wind10.1 mph W
Humidity67%
Visibility—
Dew point35°
From day 17 onward the outlook is built from 60-year climate statistics
Wed, 0446° / 29°0.06
46 °
Portal, Wednesday, 4 November
Climate normal for this date — 60-year average.
Average high46°
Average low29°
Average precipitation0.06 in
Chance of precipitation33%
Record high62° (1976)
Record low-3° (1973)
Thu, 0546° / 29°0.05
46 °
Portal, Thursday, 5 November
Climate normal for this date — 60-year average.
Average high46°
Average low29°
Average precipitation0.05 in
Chance of precipitation27%
Record high63° (1980)
Record low3° (1961)
Fri, 0644° / 27°0.05
44 °
Portal, Friday, 6 November
Climate normal for this date — 60-year average.
Average high44°
Average low27°
Average precipitation0.05 in
Chance of precipitation27%
Record high62° (2010)
Record low5° (2003)
Sat, 0744° / 28°0.04
44 °
Portal, Saturday, 7 November
Climate normal for this date — 60-year average.
Average high44°
Average low28°
Average precipitation0.04 in
Chance of precipitation32%
Record high62° (2010)
Record low2° (2017)
Sun, 0842° / 27°0.07
42 °
Portal, Sunday, 8 November
Climate normal for this date — 60-year average.
Average high42°
Average low27°
Average precipitation0.07 in
Chance of precipitation35%
Record high61° (2016)
Record low6° (2022)
Mon, 0942° / 25°0.04
42 °
Portal, Monday, 9 November
Climate normal for this date — 60-year average.
Average high42°
Average low25°
Average precipitation0.04 in
Chance of precipitation28%
Record high64° (2016)
Record low-5° (2020)
Tue, 1041° / 24°0.04
41 °
Portal, Tuesday, 10 November
Climate normal for this date — 60-year average.
Average high41°
Average low24°
Average precipitation0.04 in
Chance of precipitation25%
Record high63° (2025)
Record low-17° (1986)
Wed, 1141° / 23°0.03
41 °
Portal, Wednesday, 11 November
Climate normal for this date — 60-year average.
Average high41°
Average low23°
Average precipitation0.03 in
Chance of precipitation23%
Record high62° (2016)
Record low-12° (2000)
Thu, 1242° / 25°0.03
42 °
Portal, Thursday, 12 November
Climate normal for this date — 60-year average.
Average high42°
Average low25°
Average precipitation0.03 in
Chance of precipitation20%
Record high65° (1999)
Record low-10° (1986)
Fri, 1342° / 26°0.04
42 °
Portal, Friday, 13 November
Climate normal for this date — 60-year average.
Average high42°
Average low26°
Average precipitation0.04 in
Chance of precipitation23%
Record high63° (1999)
Record low-3° (2000)
Sat, 1441° / 25°0.03
41 °
Portal, Saturday, 14 November
Climate normal for this date — 60-year average.
Average high41°
Average low25°
Average precipitation0.03 in
Chance of precipitation23%
Record high62° (1999)
Record low1° (2000)
Sun, 1541° / 24°0.02
41 °
Portal, Sunday, 15 November
Climate normal for this date — 60-year average.
Average high41°
Average low24°
Average precipitation0.02 in
Chance of precipitation17%
Record high59° (1999)
Record low1° (2005)
Mon, 1641° / 25°0.04
41 °
Portal, Monday, 16 November
Climate normal for this date — 60-year average.
Average high41°
Average low25°
Average precipitation0.04 in
Chance of precipitation27%
Record high57° (2001)
Record low0° (1961)
Tue, 1740° / 24°0.04
40 °
Portal, Tuesday, 17 November
Climate normal for this date — 60-year average.
Average high40°
Average low24°
Average precipitation0.04 in
Chance of precipitation25%
Record high56° (1999)
Record low-2° (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 Portal, 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 Portal, 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.