Monthly outlook for Portal, MT: average high 52.8°, average low 32.9°. That is 1.6° above the climate normal for October. Precipitation is expected on 2 days (about 1.0 inches), against a normal of 4 days and 0.7 inches. The warmest day looks like 19 October (62.2°), the coolest 27 October (24.2°).
52.8°/32.9°
Average high / low
+1.6°
Above normal
2 / 4
Wet days / normal
1.0 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
19 October – 28 October
52.8°
52.1°
+0.3°
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° / 35°0
60 °
Portal, Tuesday, 20 October
Overcast. High 60°, low 35°.
Pressure30.12 inHg
Wind2.6 mph NE
Humidity49%
Visibility6.2 mi
Dew point33°
Wed, 2160° / 34°0
60 °
Portal, Wednesday, 21 October
Light rain. High 60°, low 34°.
Pressure30.00 inHg
Wind6.7 mph S
Humidity48%
Visibility6.2 mi
Dew point37°
Thu, 2260° / 38°0
60 °
Portal, Thursday, 22 October
Clear. High 60°, low 38°.
Pressure29.85 inHg
Wind8.2 mph S
Humidity50%
Visibility6.2 mi
Dew point40°
Fri, 2342° / 33°0.89
42 °
Portal, Friday, 23 October
Rain. High 42°, low 33°.
Pressure29.80 inHg
Wind11.4 mph NW
Humidity97%
Visibility—
Dew point37°
Sat, 2445° / 27°0.07
45 °
Portal, Saturday, 24 October
Light snow. High 45°, low 27°.
Pressure30.18 inHg
Wind5.3 mph N
Humidity66%
Visibility—
Dew point27°
Sun, 2559° / 31°0
59 °
Portal, Sunday, 25 October
Overcast. High 59°, low 31°.
Pressure30.15 inHg
Wind10.9 mph SW
Humidity22%
Visibility—
Dew point13°
Mon, 2643° / 26°0
43 °
Portal, Monday, 26 October
Overcast. High 43°, low 26°.
Pressure30.27 inHg
Wind8.6 mph N
Humidity60%
Visibility—
Dew point23°
Tue, 2746° / 24°0
46 °
Portal, Tuesday, 27 October
Clear. High 46°, low 24°.
Pressure30.36 inHg
Wind4.9 mph SW
Humidity47%
Visibility—
Dew point19°
Wed, 2851° / 30°0
51 °
Portal, Wednesday, 28 October
Mostly clear. High 51°, low 30°.
Pressure30.15 inHg
Wind4.4 mph SW
Humidity28%
Visibility—
Dew point13°
Thu, 2955° / 36°0
55 °
Portal, Thursday, 29 October
Overcast. High 55°, low 36°.
Pressure29.88 inHg
Wind4.9 mph SW
Humidity25%
Visibility—
Dew point16°
Fri, 3055° / 35°0
55 °
Portal, Friday, 30 October
Partly cloudy. High 55°, low 35°.
Pressure29.74 inHg
Wind9.1 mph W
Humidity31%
Visibility—
Dew point20°
Sat, 3152° / 38°0
52 °
Portal, Saturday, 31 October
Mostly clear. High 52°, low 38°.
Pressure29.83 inHg
Wind12.4 mph W
Humidity37%
Visibility—
Dew point23°
Sun, 0154° / 36°0
54 °
Portal, Sunday, 1 November
Clear. High 54°, low 36°.
Pressure29.97 inHg
Wind5.3 mph SW
Humidity42%
Visibility—
Dew point27°
Mon, 0253° / 40°0.01
53 °
Portal, Monday, 2 November
Light rain. High 53°, low 40°.
Pressure29.85 inHg
Wind12.4 mph NW
Humidity37%
Visibility—
Dew point26°
Tue, 0347° / 35°0
47 °
Portal, Tuesday, 3 November
Light rain. High 47°, low 35°.
Pressure30.09 inHg
Wind3.1 mph NW
Humidity58%
Visibility—
Dew point30°
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.