Ennis, Montana climate: Normal weather by month, frost dates and records
Ennis's normal year runs from 15°F December nights to 83°F July afternoons, with 12.9 inches of precipitation and 45 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 5.9°C, December lows of −10°C, July highs of 28°C, 329 mm of precipitation a year.
- NOAA stationEnnis
- Station IDUSC00242793
- Location45.34°N 111.71°W
- Elevation4,953 ft (1,510 m)
- Population1,081
On October 22, the normal high in Ennis is 55°F and the normal low 27°F, and the chance of measurable rain or snow is 24%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Ennis.
- Jan 34° 15°
- Feb 37° 15°
- Mar 46° 22°
- Apr 55° 28°
- May 64° 35°
- Jun 73° 41°
- Jul 83° 46°
- Aug 82° 44°
- Sep 72° 37°
- Oct 58° 29°
- Nov 43° 22°
- Dec 33° 15°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Ennis each month?
July is the warmest month, with normal highs of 83°F; December the coldest, with normal lows of 15°F. The most precipitation falls in June (2.23 in), the least in January (0.45 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 34°F | 15°F | 24.6°F | 0.45 | 6.5 | 5 | <1 | 28 | 9 h 10 min |
| February | 37°F | 15°F | 26.2°F | 0.51 | 7.6 | 6 | <1 | 25 | 10 h 20 min |
| March | 46°F | 22°F | 34.0°F | 0.84 | 6.6 | 8 | <1 | 25 | 11 h 50 min |
| April | 55°F | 28°F | 41.1°F | 1.47 | 6.0 | 11 | <1 | 20 | 13 h 30 min |
| May | 64°F | 35°F | 49.4°F | 1.93 | 1.3 | 12 | <1 | 9 | 14 h 50 min |
| June | 73°F | 41°F | 56.7°F | 2.23 | 0.2 | 11 | 1 | 1 | 15 h 40 min |
| July | 83°F | 46°F | 64.2°F | 1.16 | 0.0 | 8 | 7 | <1 | 15 h 20 min |
| August | 82°F | 44°F | 62.8°F | 1.02 | 0.0 | 7 | 5 | 1 | 14 h 10 min |
| September | 72°F | 37°F | 54.6°F | 0.97 | 0.1 | 7 | 1 | 7 | 12 h 40 min |
| October | 58°F | 29°F | 43.3°F | 1.14 | 2.2 | 8 | <1 | 18 | 11 h |
| November | 43°F | 22°F | 32.1°F | 0.69 | 6.9 | 7 | <1 | 23 | 9 h 30 min |
| December | 33°F | 15°F | 23.8°F | 0.54 | 7.3 | 6 | <1 | 28 | 8 h 50 min |
| Year (annual) | 57°F | 29°F | 42.7°F | 12.95 | 44.7 | 94 | 13 | 186 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 1°C | −9°C | −4.1°C | 11 mm | 17 cm |
| February | 3°C | −9°C | −3.2°C | 13 mm | 19 cm |
| March | 8°C | −6°C | 1.1°C | 21 mm | 17 cm |
| April | 13°C | −2°C | 5.1°C | 37 mm | 15 cm |
| May | 18°C | 2°C | 9.7°C | 49 mm | 3 cm |
| June | 23°C | 5°C | 13.7°C | 57 mm | 1 cm |
| July | 28°C | 8°C | 17.9°C | 29 mm | 0 cm |
| August | 28°C | 6°C | 17.1°C | 26 mm | 0 cm |
| September | 22°C | 3°C | 12.6°C | 25 mm | 0 cm |
| October | 14°C | −2°C | 6.3°C | 29 mm | 6 cm |
| November | 6°C | −6°C | 0.1°C | 18 mm | 18 cm |
| December | 1°C | −10°C | −4.6°C | 14 mm | 19 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00242793; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Ennis?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, August has the fewest days with rain (7).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00242793.
When is the last frost in Ennis?
In Ennis, the last spring frost (32°F) comes after June 16 in half of years and after July 6 in one year in ten; the first autumn frost comes before September 4 in half of years and before August 20 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- June 161 year in 10 after July 6; 9 in 10 after May 30
- First autumn frost, half of years before
- September 41 year in 10 before August 20; 9 in 10 before September 19
NOAA puts the median frost-free season at 78 days, and the season without a hard freeze (28°F) at 114 days.
A hard freeze (28°F) comes after May 23 in half of springs and before September 18 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Ennis in zone 5a in ZIP code 59729, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Ennis's NOAA station is in zone 5a: the coldest night of a typical year reaches −20°F (30 complete years).
Frost dates for every NOAA station in Montana · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00242793; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Ennis?
In a normal year in Ennis, 13 days a year reach 90°F, 186 nights fall to 32°F or colder and 94 days bring measurable precipitation.
- Days at 90°F or more
- 13a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 186a normal year
- Days that stay below freezing
- 38high of 32°F or less
- Days with 0.01 inch of precipitation
- 94a normal year
- Days with 1 inch of snow or more
- 15a normal year
The highest temperature in this station's record (since 1918) is 101°F, on July 13, 2026; the lowest is −43°F, on January 17, 1930.
The wettest calendar year on that record is 2010, with 17.87 in; the snowiest season is 2022–23, with 81.1 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00242793; records: ACIS (NOAA Regional Climate Centers), station USC00242793. Records use complete months only; a month missing more than three days is left out.
How sunny is Ennis?
Over a year 74% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Ennis, 4.1 kWh per square metre a day. July is the sunniest month (84%) and December the cloudiest (63%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 69% | 1.7 |
| February | 73% | 2.8 |
| March | 70% | 3.8 |
| April | 66% | 4.8 |
| May | 67% | 5.6 |
| June | 75% | 6.6 |
| July | 84% | 7.2 |
| August | 83% | 6.1 |
| September | 79% | 4.6 |
| October | 69% | 2.9 |
| November | 66% | 1.8 |
| December | 63% | 1.3 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Ennis need?
A normal year in Ennis brings 8,190 heating degree days, 52% more than the median U.S. place (5,373), and 102 cooling degree days, 89% fewer than the median (908). Nine months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,385 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,254 | 0 |
| February | 1,086 | 0 |
| March | 960 | 0 |
| April | 717 | 0 |
| May | 484 | 1 |
| June | 258 | 7 |
| July | 79 | 52 |
| August | 103 | 37 |
| September | 316 | 5 |
| October | 673 | 0 |
| November | 986 | 0 |
| December | 1,276 | 0 |
| Year (annual) | 8,190 | 102 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00242793. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Ennis been warmer than normal lately?
2025 averaged 45.7°F, 3.0°F above the 1991-2020 normal of 42.7°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 45.5°F | +2.8°F | 12.79 | 40.3 |
| 2022 | 43.1°F | +0.4°F | 15.67 | 73.3 |
| 2023 | 44.1°F | +1.4°F | 13.75 | 50.7 |
| 2024 | 46.4°F | +3.7°F | 12.62 | 43.2 |
| 2025 | 45.7°F | +3.0°F | 12.20 | 29.8 |
Over 86 complete years from 1918 to 2025, the station's annual mean temperature rose at a fitted 2.2°F per century (+0.12°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00242793; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Ennis's climate compare?
Ennis is warmer than 41 of the other 140 places with their own NOAA record in Montana, and wetter than 30. Across the 7,247 U.S. stations with normals, its annual mean of 42.7°F is warmer than 11%.
In the Köppen classification computed from these normals, Ennis is Dfb: continental, no dry season, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Ennis share this climate record?
Jeffers has no NOAA station with 1991-2020 normals of its own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Jeffers, MT52 people · 1 mi NE
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Ennis's climate
What is the coldest month in Ennis?
December, with a normal high of 33°F and a normal low of 15°F. The warmest is July (83°F by day, 46°F at night).
Does it snow in Ennis?
Yes: 45 inches in a normal year, falling on 27 days with 0.1 inch or more, the most in February (7.6 inches).
What is the rainiest month in Ennis?
June, with 2.23 in of precipitation in a normal year; the driest is January with 0.45 in.
What plant hardiness zone is Ennis in?
The USDA's 2023 map puts Ennis in zone 5a in ZIP code 59729, the nearest ZIP area. By the same method at Ennis's NOAA station, the coldest night of a typical year reaches −20°F (30 years, 1991-2020): zone 5a.
How late can frost come in Ennis?
In half of years the last 32°F night comes after June 16; in one year in ten it comes after July 6. Waiting until July 6 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Montana climateThe statewide normals and every place in the state
- Norris, MT11 miles from this station, 49.2°F a year
- Virginia City, MT12 miles from this station, 43.9°F a year
- Laurin (2 mi NE), MT19 miles from this station, 43.0°F a year
- Big Sky, MT19 miles from this station, 37.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made