As of 17:55 MDT

Weather in Grannis, MT

76°

Grannis, Thursday, 8 October, 17:55

Overcast. Feels like 74°. High 76°, low 40°.

Pressure29.91 inHg

Wind11.5 mph W

Humidity11%

Visibility6.2 mi

Dew point19°

See detailed hourly forecast

Monthly outlook for Grannis, MT: average high 50.8°, average low 31.9°. That is 1.4° below the climate normal for October. Precipitation is expected on 6 days (about 1.8 inches), against a normal of 4 days and 1.0 inches. The warmest day looks like 9 October (81.2°), the coolest 16 October (14.4°).

50.8°/31.9°

Average high / low

−1.4°

Below normal

6 / 4

Wet days / normal

1.8 in

Precipitation this month

Ten-day blocks vs climate normal

Period	Forecast high	Normal	Difference
8 October – 17 October	49.1°	54°	-2.7°
18 October – 27 October	53.7°	51.2°	+1.4°
28 October – 6 November	at normal	44.3°	—

October records over 66 years

83.1°1 October 2011All-time high

-12.3°10 October 2009All-time low

Climate normals and records are computed from the nearest reference point — Clyde Park (10 mi).

Fri, 0981° / 39°

81 °

Grannis, Friday, 9 October

Partly cloudy. High 81°, low 39°.

Pressure29.62 inHg

Wind9.9 mph S

Humidity22%

Visibility6.2 mi

Dew point29°

Sat, 1062° / 40°

0.31

62 °

Grannis, Saturday, 10 October

Rain. High 62°, low 40°.

Pressure29.56 inHg

Wind11 mph SE

Humidity34%

Visibility6.2 mi

Dew point32°

Sun, 1141° / 33°

0.41

41 °

Grannis, Sunday, 11 October

Snow. High 41°, low 33°.

Pressure30.06 inHg

Wind12.5 mph SE

Humidity89%

Visibility5.1 mi

Dew point31°

Mon, 1236° / 31°

0.04

36 °

Grannis, Monday, 12 October

Snow. High 36°, low 31°.

Pressure30.09 inHg

Wind10.6 mph SE

Humidity90%

Visibility6.2 mi

Dew point29°

Tue, 1355° / 31°

55 °

Grannis, Tuesday, 13 October

Partly cloudy. High 55°, low 31°.

Pressure29.94 inHg

Wind4.6 mph S

Humidity61%

Visibility—

Dew point35°

Wed, 1441° / 34°

0.71

41 °

Grannis, Wednesday, 14 October

Snow. High 41°, low 34°.

Pressure29.74 inHg

Wind6.5 mph SW

Humidity98%

Visibility—

Dew point39°

Thu, 1533° / 19°

0.14

33 °

Grannis, Thursday, 15 October

Snow. High 33°, low 19°.

Pressure30.50 inHg

Wind13.1 mph NW

Humidity82%

Visibility—

Dew point28°

Fri, 1630° / 14°

30 °

Grannis, Friday, 16 October

Clear. High 30°, low 14°.

Pressure30.77 inHg

Wind5.4 mph SW

Humidity81%

Visibility—

Dew point20°

Sat, 1737° / 21°

37 °

Grannis, Saturday, 17 October

Clear. High 37°, low 21°.

Pressure30.45 inHg

Wind5.1 mph SW

Humidity86%

Visibility—

Dew point30°

Sun, 1844° / 31°

44 °

Grannis, Sunday, 18 October

Partly cloudy. High 44°, low 31°.

Pressure30.03 inHg

Wind8.2 mph SW

Humidity98%

Visibility—

Dew point41°

Mon, 1943° / 37°

0.17

43 °

Grannis, Monday, 19 October

Rain. High 43°, low 37°.

Pressure30.18 inHg

Wind8.4 mph SW

Humidity96%

Visibility—

Dew point39°

Tue, 2053° / 34°

53 °

Grannis, Tuesday, 20 October

Clear. High 53°, low 34°.

Pressure30.15 inHg

Wind10.8 mph SW

Humidity61%

Visibility—

Dew point35°

Wed, 2159° / 34°

59 °

Grannis, Wednesday, 21 October

Overcast. High 59°, low 34°.

Pressure30.12 inHg

Wind8.2 mph SW

Humidity48%

Visibility—

Dew point31°

Thu, 2262° / 36°

62 °

Grannis, Thursday, 22 October

Clear. High 62°, low 36°.

Pressure30.12 inHg

Wind7.2 mph SW

Humidity39%

Visibility—

Dew point28°

Fri, 2362° / 37°

62 °

Grannis, Friday, 23 October

Partly cloudy. High 62°, low 37°.

Pressure29.97 inHg

Wind6.9 mph SW

Humidity38%

Visibility—

Dew point28°

From day 17 onward the outlook is built from 60-year climate statistics

Sat, 2450° / 31°

0.04

50 °

Grannis, Saturday, 24 October

Climate normal for this date — 60-year average.

Average high50°

Average low31°

Average precipitation0.04 in

Chance of precipitation28%

Record high65° (1992)

Record low8° (2020)

Sun, 2550° / 31°

0.04

50 °

Grannis, Sunday, 25 October

Climate normal for this date — 60-year average.

Average high50°

Average low31°

Average precipitation0.04 in

Chance of precipitation22%

Record high68° (2014)

Record low0° (2020)

Mon, 2649° / 31°

0.07

49 °

Grannis, Monday, 26 October

Climate normal for this date — 60-year average.

Average high49°

Average low31°

Average precipitation0.07 in

Chance of precipitation35%

Record high65° (1999)

Record low-4° (2020)

Tue, 2748° / 29°

0.04

48 °

Grannis, Tuesday, 27 October

Climate normal for this date — 60-year average.

Average high48°

Average low29°

Average precipitation0.04 in

Chance of precipitation25%

Record high68° (2024)

Record low2° (2019)

Wed, 2847° / 29°

0.06

47 °

Grannis, Wednesday, 28 October

Climate normal for this date — 60-year average.

Average high47°

Average low29°

Average precipitation0.06 in

Chance of precipitation27%

Record high65° (1987)

Record low4° (1971)

Thu, 2945° / 28°

0.06

45 °

Grannis, Thursday, 29 October

Climate normal for this date — 60-year average.

Average high45°

Average low28°

Average precipitation0.06 in

Chance of precipitation28%

Record high65° (1987)

Record low-8° (2019)

Fri, 3045° / 27°

0.04

45 °

Grannis, Friday, 30 October

Climate normal for this date — 60-year average.

Average high45°

Average low27°

Average precipitation0.04 in

Chance of precipitation25%

Record high66° (1987)

Record low-10° (1972)

Sat, 3144° / 26°

0.06

44 °

Grannis, Saturday, 31 October

Climate normal for this date — 60-year average.

Average high44°

Average low26°

Average precipitation0.06 in

Chance of precipitation27%

Record high64° (2014)

Record low-12° (2002)

Sun, 0144° / 26°

0.06

44 °

Grannis, Sunday, 1 November

Climate normal for this date — 60-year average.

Average high44°

Average low26°

Average precipitation0.06 in

Chance of precipitation25%

Record high67° (2025)

Record low-3° (1989)

Mon, 0243° / 26°

0.03

43 °

Grannis, Monday, 2 November

Climate normal for this date — 60-year average.

Average high43°

Average low26°

Average precipitation0.03 in

Chance of precipitation25%

Record high61° (2020)

Record low-10° (1995)

Tue, 0344° / 27°

0.04

44 °

Grannis, Tuesday, 3 November

Climate normal for this date — 60-year average.

Average high44°

Average low27°

Average precipitation0.04 in

Chance of precipitation22%

Record high63° (2020)

Record low-1° (1995)

Wed, 0444° / 27°

0.05

44 °

Grannis, Wednesday, 4 November

Climate normal for this date — 60-year average.

Average high44°

Average low27°

Average precipitation0.05 in

Chance of precipitation30%

Record high61° (2020)

Record low-6° (1973)

Thu, 0544° / 27°

0.06

44 °

Grannis, Thursday, 5 November

Climate normal for this date — 60-year average.

Average high44°

Average low27°

Average precipitation0.06 in

Chance of precipitation38%

Record high66° (2020)

Record low-5° (2003)

Fri, 0643° / 26°

0.05

43 °

Grannis, Friday, 6 November

Climate normal for this date — 60-year average.

Average high43°

Average low26°

Average precipitation0.05 in

Chance of precipitation27%

Record high62° (1999)

Record low2° (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 Grannis, 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 Grannis, 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.