Monthly outlook for Lanark, MT: average high 55.1°, average low 41.2°. That is 0.7° below the climate normal for October. Precipitation is expected on 3 days (about 0.9 inches), against a normal of 3 days and 0.5 inches. The warmest day looks like 9 October (82.5°), the coolest 16 October (33°).
55.1°/41.2°
Average high / low
−0.7°
Below normal
3 / 3
Wet days / normal
0.9 in
Precipitation this month
Ten-day blocks vs climate normal
Period
Forecast high
Normal
Difference
9 October – 18 October
55°
57.1°
-1.1°
19 October – 28 October
55.2°
53.7°
+0.8°
29 October – 7 November
at normal
46.5°
—
October records over 66 years
90.3°1 October 1992All-time high
-4.4°31 October 2023All-time low
Climate normals and records are computed from the nearest reference point — Culbertson (7 mi).
Sat, 1064° / 49°0
64 °
Lanark, Saturday, 10 October
Light rain. High 64°, low 49°.
Pressure29.59 inHg
Wind13.4 mph NW
Humidity40%
Visibility6.2 mi
Dew point39°
Sun, 1148° / 39°0.24
48 °
Lanark, Sunday, 11 October
Rain. High 48°, low 39°.
Pressure30.09 inHg
Wind16.3 mph NE
Humidity83%
Visibility6.2 mi
Dew point36°
Mon, 1239° / 35°0.48
39 °
Lanark, Monday, 12 October
Light rain. High 39°, low 35°.
Pressure30.09 inHg
Wind11.3 mph NE
Humidity96%
Visibility2.8 mi
Dew point36°
Tue, 1345° / 36°0.03
45 °
Lanark, Tuesday, 13 October
Light rain. High 45°, low 36°.
Pressure30.15 inHg
Wind4.8 mph SW
Humidity76%
Visibility—
Dew point34°
Wed, 1454° / 34°0
54 °
Lanark, Wednesday, 14 October
Overcast. High 54°, low 34°.
Pressure29.91 inHg
Wind8.9 mph SE
Humidity71%
Visibility—
Dew point37°
Thu, 1550° / 38°0
50 °
Lanark, Thursday, 15 October
Light rain. High 50°, low 38°.
Pressure30.09 inHg
Wind28.3 mph NW
Humidity66%
Visibility—
Dew point32°
Fri, 1646° / 33°0
46 °
Lanark, Friday, 16 October
Overcast. High 46°, low 33°.
Pressure30.45 inHg
Wind27.1 mph NW
Humidity40%
Visibility—
Dew point17°
Sat, 1761° / 38°0
61 °
Lanark, Saturday, 17 October
Overcast. High 61°, low 38°.
Pressure29.97 inHg
Wind16.6 mph W
Humidity28%
Visibility—
Dew point22°
Sun, 1861° / 45°0
61 °
Lanark, Sunday, 18 October
Overcast. High 61°, low 45°.
Pressure30.00 inHg
Wind7.3 mph NE
Humidity31%
Visibility—
Dew point26°
Mon, 1960° / 44°0
60 °
Lanark, Monday, 19 October
Overcast. High 60°, low 44°.
Pressure30.03 inHg
Wind16 mph E
Humidity40%
Visibility—
Dew point30°
Tue, 2060° / 47°0
60 °
Lanark, Tuesday, 20 October
Overcast. High 60°, low 47°.
Pressure29.85 inHg
Wind10.5 mph N
Humidity55%
Visibility—
Dew point39°
Wed, 2153° / 44°0
53 °
Lanark, Wednesday, 21 October
Overcast. High 53°, low 44°.
Pressure30.27 inHg
Wind9.8 mph N
Humidity63%
Visibility—
Dew point38°
Thu, 2254° / 41°0
54 °
Lanark, Thursday, 22 October
Mostly clear. High 54°, low 41°.
Pressure30.39 inHg
Wind10.1 mph SE
Humidity56%
Visibility—
Dew point34°
Fri, 2351° / 44°0.11
51 °
Lanark, Friday, 23 October
Light rain. High 51°, low 44°.
Pressure30.12 inHg
Wind15 mph SE
Humidity70%
Visibility—
Dew point41°
Sat, 2453° / 47°0
53 °
Lanark, Saturday, 24 October
Light rain. High 53°, low 47°.
Pressure29.97 inHg
Wind8.5 mph W
Humidity88%
Visibility—
Dew point46°
From day 17 onward the outlook is built from 60-year climate statistics
Sun, 2553° / 35°0.03
53 °
Lanark, Sunday, 25 October
Climate normal for this date — 60-year average.
Average high53°
Average low35°
Average precipitation0.03 in
Chance of precipitation12%
Record high74° (1990)
Record low6° (2020)
Mon, 2653° / 35°0.03
53 °
Lanark, Monday, 26 October
Climate normal for this date — 60-year average.
Average high53°
Average low35°
Average precipitation0.03 in
Chance of precipitation20%
Record high73° (1983)
Record low4° (2020)
Tue, 2751° / 33°0.04
51 °
Lanark, Tuesday, 27 October
Climate normal for this date — 60-year average.
Average high51°
Average low33°
Average precipitation0.04 in
Chance of precipitation20%
Record high73° (1983)
Record low7° (2023)
Wed, 2850° / 33°0.03
50 °
Lanark, Wednesday, 28 October
Climate normal for this date — 60-year average.
Average high50°
Average low33°
Average precipitation0.03 in
Chance of precipitation15%
Record high74° (1990)
Record low11° (2023)
Thu, 2948° / 32°0.05
48 °
Lanark, Thursday, 29 October
Climate normal for this date — 60-year average.
Average high48°
Average low32°
Average precipitation0.05 in
Chance of precipitation22%
Record high72° (1968)
Record low10° (1991)
Fri, 3048° / 31°0.03
48 °
Lanark, Friday, 30 October
Climate normal for this date — 60-year average.
Average high48°
Average low31°
Average precipitation0.03 in
Chance of precipitation15%
Record high70° (1983)
Record low-2° (1991)
Sat, 3148° / 31°0.02
48 °
Lanark, Saturday, 31 October
Climate normal for this date — 60-year average.
Average high48°
Average low31°
Average precipitation0.02 in
Chance of precipitation17%
Record high76° (1990)
Record low-4° (2023)
Sun, 0147° / 32°0.04
47 °
Lanark, Sunday, 1 November
Climate normal for this date — 60-year average.
Average high47°
Average low32°
Average precipitation0.04 in
Chance of precipitation15%
Record high69° (1965)
Record low2° (1984)
Mon, 0246° / 30°0.02
46 °
Lanark, Monday, 2 November
Climate normal for this date — 60-year average.
Average high46°
Average low30°
Average precipitation0.02 in
Chance of precipitation13%
Record high71° (1965)
Record low3° (1991)
Tue, 0346° / 30°0.02
46 °
Lanark, Tuesday, 3 November
Climate normal for this date — 60-year average.
Average high46°
Average low30°
Average precipitation0.02 in
Chance of precipitation15%
Record high66° (1981)
Record low-4° (1991)
Wed, 0447° / 30°0.03
47 °
Lanark, Wednesday, 4 November
Climate normal for this date — 60-year average.
Average high47°
Average low30°
Average precipitation0.03 in
Chance of precipitation23%
Record high69° (1975)
Record low8° (1991)
Thu, 0546° / 29°0.02
46 °
Lanark, Thursday, 5 November
Climate normal for this date — 60-year average.
Average high46°
Average low29°
Average precipitation0.02 in
Chance of precipitation13%
Record high71° (2020)
Record low-1° (2003)
Fri, 0645° / 28°0.02
45 °
Lanark, Friday, 6 November
Climate normal for this date — 60-year average.
Average high45°
Average low28°
Average precipitation0.02 in
Chance of precipitation17%
Record high66° (2009)
Record low0° (1991)
Sat, 0745° / 28°0.02
45 °
Lanark, Saturday, 7 November
Climate normal for this date — 60-year average.
Average high45°
Average low28°
Average precipitation0.02 in
Chance of precipitation10%
Record high73° (1999)
Record low-3° (1991)
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 Lanark, 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 Lanark, 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.