St. Peter, Minnesota climate: Normal weather by month, frost dates and records
St. Peter's normal year runs from 3°F January nights to 82°F July afternoons, with 32.4 inches of precipitation and 38 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.6°C, January lows of −16°C, July highs of 28°C, 823 mm of precipitation a year.
- NOAA stationSt Peter
- Station IDUSC00217405
- Location44.32°N 93.97°W
- Elevation795 ft (242 m)
- Population12,456
On October 23, the normal high in St. Peter is 55°F and the normal low 32°F, and the chance of measurable rain or snow is 20%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for St. Peter.
- Jan 22° 3°
- Feb 27° 7°
- Mar 40° 21°
- Apr 55° 33°
- May 68° 46°
- Jun 78° 57°
- Jul 82° 61°
- Aug 79° 59°
- Sep 72° 49°
- Oct 58° 35°
- Nov 42° 23°
- Dec 28° 11°
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. Peter each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 3°F. The most precipitation falls in June (5.13 in), the least in January (0.96 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 22°F | 3°F | 12.5°F | 0.96 | 8.8 | 5 | <1 | 31 | 9 h 10 min |
| February | 27°F | 7°F | 16.8°F | 0.96 | 8.2 | 4 | <1 | 27 | 10 h 30 min |
| March | 40°F | 21°F | 30.3°F | 1.79 | 4.2 | 6 | <1 | 26 | 11 h 50 min |
| April | 55°F | 33°F | 43.9°F | 3.06 | 2.7 | 8 | <1 | 12 | 13 h 20 min |
| May | 68°F | 46°F | 57.0°F | 4.04 | 0.0 | 10 | 1 | 1 | 14 h 40 min |
| June | 78°F | 57°F | 67.4°F | 5.13 | 0.0 | 11 | 3 | <1 | 15 h 30 min |
| July | 82°F | 61°F | 71.5°F | 4.41 | 0.0 | 9 | 4 | <1 | 15 h 10 min |
| August | 79°F | 59°F | 69.1°F | 3.56 | 0.0 | 8 | 2 | <1 | 14 h 10 min |
| September | 72°F | 49°F | 60.4°F | 3.16 | 0.0 | 7 | 1 | 1 | 12 h 40 min |
| October | 58°F | 35°F | 46.8°F | 2.50 | 0.2 | 7 | <1 | 10 | 11 h |
| November | 42°F | 23°F | 32.2°F | 1.68 | 3.2 | 5 | <1 | 24 | 9 h 40 min |
| December | 28°F | 11°F | 19.2°F | 1.17 | 10.6 | 5 | <1 | 30 | 8 h 50 min |
| Year (annual) | 54°F | 34°F | 43.9°F | 32.42 | 37.9 | 85 | 11 | 163 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −6°C | −16°C | −10.8°C | 24 mm | 22 cm |
| February | −3°C | −14°C | −8.4°C | 24 mm | 21 cm |
| March | 4°C | −6°C | −0.9°C | 45 mm | 11 cm |
| April | 13°C | 0°C | 6.6°C | 78 mm | 7 cm |
| May | 20°C | 8°C | 13.9°C | 103 mm | 0 cm |
| June | 25°C | 14°C | 19.7°C | 130 mm | 0 cm |
| July | 28°C | 16°C | 21.9°C | 112 mm | 0 cm |
| August | 26°C | 15°C | 20.6°C | 90 mm | 0 cm |
| September | 22°C | 9°C | 15.8°C | 80 mm | 0 cm |
| October | 15°C | 2°C | 8.2°C | 64 mm | 1 cm |
| November | 5°C | −5°C | 0.1°C | 43 mm | 8 cm |
| December | −2°C | −12°C | −7.1°C | 30 mm | 27 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00217405; 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. Peter?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September 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 USC00217405.
When is the last frost in St. Peter?
In St. Peter, the last spring frost (32°F) comes after May 2 in half of years and after May 14 in one year in ten; the first autumn frost comes before October 4 in half of years and before September 21 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 21 year in 10 after May 14; 9 in 10 after April 19
- First autumn frost, half of years before
- October 41 year in 10 before September 21; 9 in 10 before October 16
NOAA puts the median frost-free season at 153 days, and the season without a hard freeze (28°F) at 173 days.
A hard freeze (28°F) comes after April 22 in half of springs and before October 13 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts St. Peter in zone 4b in ZIP code 56082, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, St. Peter's NOAA station is in zone 5a: the coldest night of a typical year reaches −20°F (20 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Minnesota · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00217405; 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. Peter?
In a normal year in St. Peter, 11 days a year reach 90°F, 163 nights fall to 32°F or colder and 85 days bring measurable precipitation.
- Days at 90°F or more
- 11a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 163a normal year
- Days that stay below freezing
- 75high of 32°F or less
- Days with 0.01 inch of precipitation
- 85a normal year
- Days with 1 inch of snow or more
- 11a normal year
The highest temperature in this station's record (since 1893) is 109°F, on July 14, 1936; the lowest is −40°F, on January 12, 1912.
The wettest calendar year on that record is 2016, with 46.35 in; the snowiest season is 1951–52, with 89.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00217405; records: ACIS (NOAA Regional Climate Centers), station USC00217405. Records use complete months only; a month missing more than three days is left out.
How sunny is St. Peter?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around St. Peter, 3.9 kWh per square metre a day. July is the sunniest month (82%) and December the cloudiest (62%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 72% | 1.8 |
| February | 78% | 3.0 |
| March | 69% | 3.7 |
| April | 68% | 4.7 |
| May | 69% | 5.4 |
| June | 74% | 6.0 |
| July | 82% | 6.4 |
| August | 79% | 5.4 |
| September | 76% | 4.2 |
| October | 69% | 2.7 |
| November | 67% | 1.8 |
| December | 62% | 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 St. Peter need?
A normal year in St. Peter brings 8,214 heating degree days, 53% more than the median U.S. place (5,373), and 577 cooling degree days, 36% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,518 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,627 | 0 |
| February | 1,350 | 0 |
| March | 1,077 | 0 |
| April | 636 | 2 |
| May | 278 | 32 |
| June | 53 | 125 |
| July | 10 | 213 |
| August | 27 | 154 |
| September | 184 | 48 |
| October | 568 | 4 |
| November | 983 | 0 |
| December | 1,420 | 0 |
| Year (annual) | 8,214 | 577 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00217405. 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. Peter been warmer than normal lately?
2025 averaged 45.9°F, 2.0°F above the 1991-2020 normal of 43.9°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 46.7°F | +2.8°F | 27.34 | 35.4 |
| 2022 | 42.8°F | −1.1°F | – | 42.7 |
| 2023 | 46.3°F | +2.4°F | – | 40.1 |
| 2024 | 47.7°F | +3.8°F | – | – |
| 2025 | 45.9°F | +2.0°F | – | – |
Over 75 complete years from 1894 to 2024, the station's annual mean temperature rose at a fitted 1.8°F per century (+0.10°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00217405; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does St. Peter's climate compare?
St. Peter is warmer than 75 of the other 128 places with their own NOAA record in Minnesota, and wetter than 86. Across the 7,247 U.S. stations with normals, its annual mean of 43.9°F is warmer than 15%.
In the Köppen classification computed from these normals, St. Peter 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 St. Peter share this climate record?
6 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.
- Le Sueur, MN4,230 people · 11 mi N
- Le Center, MN2,528 people · 12 mi E
- Nicollet, MN1,114 people · 11 mi W
- Henderson, MN988 people · 14 mi N
- Cleveland, MN769 people · 6 mi E
- Kasota, MN718 people · 2 mi S
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. Peter's climate
What is the coldest month in St. Peter?
January, with a normal high of 22°F and a normal low of 3°F. The warmest is July (82°F by day, 61°F at night).
Does it snow in St. Peter?
Yes: 38 inches in a normal year, falling on 15 days with 0.1 inch or more, the most in December (10.6 inches).
What is the rainiest month in St. Peter?
June, with 5.13 in of precipitation in a normal year; the driest is January with 0.96 in.
What plant hardiness zone is St. Peter in?
The USDA's 2023 map puts St. Peter in zone 4b in ZIP code 56082, the nearest ZIP area. By the same method at St. Peter's NOAA station, the coldest night of a typical year reaches −20°F (20 years, 1991-2020): zone 5a.
How late can frost come in St. Peter?
In half of years the last 32°F night comes after May 2; in one year in ten it comes after May 14. Waiting until May 14 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Minnesota climateThe statewide normals and every place in the state
- Mankato, MN12 miles from this station, 45.3°F a year
- Gaylord, MN21 miles from this station, 44.9°F a year
- New Ulm, MN26 miles from this station, 45.9°F a year
- Waseca, MN28 miles from this station, 44.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made