St. Maries, Idaho climate: Normal weather by month, frost dates and records
St. Maries's normal year runs from 24°F December nights to 84°F July afternoons, with 31.1 inches of precipitation and 56 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.8°C, December lows of −4°C, July highs of 29°C, 790 mm of precipitation a year.
- NOAA stationSaint Maries
- Station IDUSC00108062
- Location47.32°N 116.58°W
- Elevation2,151 ft (656 m)
- Population2,487
On October 14, the normal high in St. Maries is 60°F and the normal low 36°F, and the chance of measurable rain or snow is 34%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for St. Maries.
- Jan 37° 24°
- Feb 42° 25°
- Mar 50° 30°
- Apr 58° 35°
- May 68° 42°
- Jun 74° 48°
- Jul 84° 52°
- Aug 85° 51°
- Sep 75° 44°
- Oct 59° 36°
- Nov 44° 30°
- Dec 36° 24°
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 St. Maries each month?
July is the warmest month, with normal highs of 84°F; December the coldest, with normal lows of 24°F. The most precipitation falls in December (4.44 in), the least in August (0.74 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 37°F | 24°F | 30.4°F | 4.41 | 16.3 | 16 | <1 | 26 | 8 h 50 min |
| February | 42°F | 25°F | 33.4°F | 2.99 | 8.6 | 13 | <1 | 22 | 10 h 10 min |
| March | 50°F | 30°F | 39.5°F | 3.28 | 5.2 | 14 | <1 | 21 | 11 h 50 min |
| April | 58°F | 35°F | 46.5°F | 2.30 | 0.7 | 13 | <1 | 10 | 13 h 30 min |
| May | 68°F | 42°F | 54.9°F | 2.43 | 0.1 | 12 | <1 | 2 | 15 h |
| June | 74°F | 48°F | 60.8°F | 2.12 | 0.0 | 11 | 1 | <1 | 15 h 50 min |
| July | 84°F | 52°F | 68.2°F | 0.79 | 0.0 | 5 | 8 | <1 | 15 h 40 min |
| August | 85°F | 51°F | 67.8°F | 0.74 | 0.0 | 4 | 8 | <1 | 14 h 20 min |
| September | 75°F | 44°F | 59.1°F | 1.04 | 0.0 | 6 | 2 | 1 | 12 h 40 min |
| October | 59°F | 36°F | 47.2°F | 2.42 | 0.2 | 11 | <1 | 10 | 11 h |
| November | 44°F | 30°F | 36.6°F | 4.15 | 6.6 | 15 | <1 | 19 | 9 h 20 min |
| December | 36°F | 24°F | 30.1°F | 4.44 | 18.3 | 16 | <1 | 27 | 8 h 30 min |
| Year (annual) | 59°F | 37°F | 47.9°F | 31.11 | 56.0 | 136 | 20 | 138 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 3°C | −4°C | −0.9°C | 112 mm | 41 cm |
| February | 5°C | −4°C | 0.8°C | 76 mm | 22 cm |
| March | 10°C | −1°C | 4.2°C | 83 mm | 13 cm |
| April | 14°C | 2°C | 8.1°C | 58 mm | 2 cm |
| May | 20°C | 6°C | 12.7°C | 62 mm | 0 cm |
| June | 23°C | 9°C | 16.0°C | 54 mm | 0 cm |
| July | 29°C | 11°C | 20.1°C | 20 mm | 0 cm |
| August | 29°C | 11°C | 19.9°C | 19 mm | 0 cm |
| September | 24°C | 7°C | 15.1°C | 26 mm | 0 cm |
| October | 15°C | 2°C | 8.4°C | 61 mm | 1 cm |
| November | 7°C | −1°C | 2.6°C | 105 mm | 17 cm |
| December | 2°C | −4°C | −1.1°C | 113 mm | 46 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00108062; 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 St. Maries?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, August has the fewest days with rain (4).
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 USC00108062.
When is the last frost in St. Maries?
In St. Maries, the last spring frost (32°F) comes after May 3 in half of years and after May 18 in one year in ten; the first autumn frost comes before October 4 in half of years and before September 18 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
- May 31 year in 10 after May 18; 9 in 10 after April 20
- First autumn frost, half of years before
- October 41 year in 10 before September 18; 9 in 10 before October 20
NOAA puts the median frost-free season at 152 days, and the season without a hard freeze (28°F) at 188 days.
A hard freeze (28°F) comes after April 14 in half of springs and before October 19 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts St. Maries in zone 6b in ZIP code 83861, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, St. Maries's NOAA station is in zone 6b: the coldest night of a typical year reaches −1°F (25 complete years).
Frost dates for every NOAA station in Idaho · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00108062; 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 St. Maries?
In a normal year in St. Maries, 20 days a year reach 90°F (1 of them 100°F or more), 138 nights fall to 32°F or colder and 136 days bring measurable precipitation.
- Days at 90°F or more
- 20a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 138a normal year
- Days that stay below freezing
- 22high of 32°F or less
- Days with 0.01 inch of precipitation
- 136a normal year
- Days with 1 inch of snow or more
- 17a normal year
The highest temperature in this station's record (since 1897) is 110°F, on August 11, 2018; the lowest is −29°F, on December 30, 1968.
The wettest calendar year on that record is 1996, with 46.95 in; the snowiest season is 1996–97, with 146.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00108062; records: ACIS (NOAA Regional Climate Centers), station USC00108062. Records use complete months only; a month missing more than three days is left out.
How sunny is St. Maries?
Over a year 74% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around St. Maries, 3.8 kWh per square metre a day. July is the sunniest month (90%) and December the cloudiest (50%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 53% | 1.1 |
| February | 62% | 2.0 |
| March | 61% | 3.1 |
| April | 67% | 4.6 |
| May | 74% | 5.9 |
| June | 75% | 6.5 |
| July | 90% | 7.4 |
| August | 88% | 6.1 |
| September | 81% | 4.4 |
| October | 71% | 2.6 |
| November | 56% | 1.3 |
| December | 50% | 0.9 |
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 St. Maries need?
A normal year in St. Maries brings 6,553 heating degree days, 22% more than the median U.S. place (5,373), and 331 cooling degree days, 64% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,995 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,071 | 0 |
| February | 886 | 0 |
| March | 789 | 0 |
| April | 557 | 0 |
| May | 321 | 8 |
| June | 161 | 33 |
| July | 40 | 139 |
| August | 42 | 128 |
| September | 200 | 23 |
| October | 554 | 0 |
| November | 851 | 0 |
| December | 1,082 | 0 |
| Year (annual) | 6,553 | 331 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00108062. 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 St. Maries been warmer than normal lately?
Over 77 complete years from 1898 to 2018, the station's annual mean temperature rose at a fitted 2.1°F per century (+0.12°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does St. Maries's climate compare?
St. Maries is warmer than 55 of the other 84 places with their own NOAA record in Idaho, and wetter than 74. Across the 7,247 U.S. stations with normals, its annual mean of 47.9°F is warmer than 31%.
In the Köppen classification computed from these normals, St. Maries is Dsb: continental, dry-summer, 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 St. Maries share this climate record?
2 places have no NOAA station with 1991-2020 normals of their 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.
- Fernwood, ID130 people · 17 mi SE
- Parkline, ID62 people · 6 mi W
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 St. Maries's climate
What is the coldest month in St. Maries?
December, with a normal high of 36°F and a normal low of 24°F. The warmest is July (84°F by day, 52°F at night).
Does it snow in St. Maries?
Yes: 56 inches in a normal year, falling on 32 days with 0.1 inch or more, the most in December (18.3 inches).
What is the rainiest month in St. Maries?
December, with 4.44 in of precipitation in a normal year; the driest is August with 0.74 in.
What plant hardiness zone is St. Maries in?
The USDA's 2023 map puts St. Maries in zone 6b in ZIP code 83861, the nearest ZIP area. By the same method at St. Maries's NOAA station, the coldest night of a typical year reaches −1°F (25 years, 1991-2020): zone 6b.
How late can frost come in St. Maries?
In half of years the last 32°F night comes after May 3; in one year in ten it comes after May 18. Waiting until May 18 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Idaho climateThe statewide normals and every place in the state
- Plummer, ID17 miles from this station, 46.5°F a year
- Kellogg, ID26 miles from this station, 46.7°F a year
- Coeur d'Alene, ID27 miles from this station, 48.8°F a year
- Potlatch, ID28 miles from this station, 46.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made