Monthly outlook for Portal, MT: average high 43.5°, average low 28.1°. That is 1.5° below the climate normal for October. Precipitation is expected on 4 days (about 0.5 inches), against a normal of 4 days and 0.7 inches. The warmest day looks like 6 November (57.6°), the coolest 29 October (17.6°).
43.5°/28.1°
Average high / low
−1.5°
Below normal
4 / 4
Wet days / normal
0.5 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
25 October – 3 November
41.2°
47.5°
-3.5°
4 November – 13 November
47.5°
43°
+2.5°
14 November – 23 November
at normal
38.8°
—
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).
Mon, 2641° / 23°0.03
41 °
Portal, Monday, 26 October
Light snow. High 41°, low 23°.
Pressure30.06 inHg
Wind4.3 mph S
Humidity69%
Visibility6.2 mi
Dew point26°
Tue, 2738° / 23°0.12
38 °
Portal, Tuesday, 27 October
Snow. High 38°, low 23°.
Pressure29.88 inHg
Wind8.6 mph W
Humidity74%
Visibility6.2 mi
Dew point25°
Wed, 2839° / 21°0.11
39 °
Portal, Wednesday, 28 October
Snow. High 39°, low 21°.
Pressure29.94 inHg
Wind9.3 mph S
Humidity72%
Visibility6.2 mi
Dew point23°
Thu, 2937° / 18°0.01
37 °
Portal, Thursday, 29 October
Light snow. High 37°, low 18°.
Pressure30.06 inHg
Wind3.6 mph SW
Humidity73%
Visibility—
Dew point26°
Fri, 3038° / 22°0.02
38 °
Portal, Friday, 30 October
Light rain. High 38°, low 22°.
Pressure30.06 inHg
Wind3.3 mph W
Humidity86%
Visibility—
Dew point28°
Sat, 3148° / 33°0
48 °
Portal, Saturday, 31 October
Overcast. High 48°, low 33°.
Pressure29.91 inHg
Wind11.6 mph SW
Humidity47%
Visibility—
Dew point25°
Sun, 0148° / 32°0
48 °
Portal, Sunday, 1 November
Overcast. High 48°, low 32°.
Pressure29.68 inHg
Wind6.6 mph SW
Humidity42%
Visibility—
Dew point22°
Mon, 0242° / 29°0
42 °
Portal, Monday, 2 November
Overcast. High 42°, low 29°.
Pressure30.00 inHg
Wind11.1 mph W
Humidity45%
Visibility—
Dew point20°
Tue, 0346° / 30°0
46 °
Portal, Tuesday, 3 November
Overcast. High 46°, low 30°.
Pressure29.94 inHg
Wind8.6 mph SW
Humidity37%
Visibility—
Dew point17°
Wed, 0446° / 33°0
46 °
Portal, Wednesday, 4 November
Partly cloudy. High 46°, low 33°.
Pressure29.91 inHg
Wind12.8 mph W
Humidity48%
Visibility—
Dew point25°
Thu, 0552° / 34°0
52 °
Portal, Thursday, 5 November
Overcast. High 52°, low 34°.
Pressure29.85 inHg
Wind10.8 mph S
Humidity42%
Visibility—
Dew point25°
Fri, 0658° / 40°0
58 °
Portal, Friday, 6 November
Overcast. High 58°, low 40°.
Pressure29.71 inHg
Wind10.2 mph S
Humidity44%
Visibility—
Dew point31°
Sat, 0750° / 33°0.13
50 °
Portal, Saturday, 7 November
Snow. High 50°, low 33°.
Pressure29.38 inHg
Wind12.7 mph W
Humidity56%
Visibility—
Dew point33°
Sun, 0841° / 28°0
41 °
Portal, Sunday, 8 November
Clear. High 41°, low 28°.
Pressure29.85 inHg
Wind12 mph SW
Humidity58%
Visibility—
Dew point25°
Mon, 0938° / 29°0.04
38 °
Portal, Monday, 9 November
Light snow. High 38°, low 29°.
Pressure30.33 inHg
Wind22.6 mph W
Humidity48%
Visibility—
Dew point17°
From day 17 onward the outlook is built from 60-year climate statistics
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)
Wed, 1839° / 23°0.05
39 °
Portal, Wednesday, 18 November
Climate normal for this date — 60-year average.
Average high39°
Average low23°
Average precipitation0.05 in
Chance of precipitation30%
Record high58° (2008)
Record low-12° (2022)
Thu, 1938° / 22°0.06
38 °
Portal, Thursday, 19 November
Climate normal for this date — 60-year average.
Average high38°
Average low22°
Average precipitation0.06 in
Chance of precipitation28%
Record high53° (1989)
Record low-3° (1978)
Fri, 2038° / 22°0.03
38 °
Portal, Friday, 20 November
Climate normal for this date — 60-year average.
Average high38°
Average low22°
Average precipitation0.03 in
Chance of precipitation28%
Record high56° (2002)
Record low-4° (1985)
Sat, 2137° / 20°0.03
37 °
Portal, Saturday, 21 November
Climate normal for this date — 60-year average.
Average high37°
Average low20°
Average precipitation0.03 in
Chance of precipitation22%
Record high55° (2002)
Record low-4° (2010)
Sun, 2236° / 20°0.04
36 °
Portal, Sunday, 22 November
Climate normal for this date — 60-year average.
Average high36°
Average low20°
Average precipitation0.04 in
Chance of precipitation28%
Record high55° (2021)
Record low-13° (1985)
Mon, 2336° / 19°0.04
36 °
Portal, Monday, 23 November
Climate normal for this date — 60-year average.
Average high36°
Average low19°
Average precipitation0.04 in
Chance of precipitation22%
Record high53° (2025)
Record low-20° (1985)
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.