St. Johns, Michigan climate: Normal weather by month, frost dates and records
St. Johns's normal year runs from 18°F January nights to 83°F July afternoons, with 34.0 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.5°C, January lows of −8°C, July highs of 28°C, 864 mm of precipitation a year.
- NOAA stationSaint Johns
- Station IDUSC00207280
- Location43.01°N 84.55°W
- Elevation743 ft (227 m)
- From the centerunder 1 mile
- Population7,723
On October 14, the normal high in St. Johns is 63°F and the normal low 43°F, and the chance of measurable rain or snow is 37%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for St. Johns.
- Jan 31° 18°
- Feb 33° 19°
- Mar 44° 26°
- Apr 57° 36°
- May 69° 48°
- Jun 79° 59°
- Jul 83° 62°
- Aug 81° 61°
- Sep 75° 53°
- Oct 62° 43°
- Nov 47° 33°
- 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. Johns each month?
July is the warmest month, with normal highs of 83°F; January the coldest, with normal lows of 18°F. The most precipitation falls in May (3.83 in), the least in February (1.80 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 31°F | 18°F | 24.2°F | 2.07 | 13 | <1 | 29 | 9 h 20 min |
| February | 33°F | 19°F | 25.8°F | 1.80 | 10 | <1 | 27 | 10 h 30 min |
| March | 44°F | 26°F | 34.9°F | 1.93 | 10 | <1 | 25 | 11 h 50 min |
| April | 57°F | 36°F | 46.6°F | 3.58 | 12 | <1 | 13 | 13 h 20 min |
| May | 69°F | 48°F | 58.8°F | 3.83 | 12 | 1 | 1 | 14 h 40 min |
| June | 79°F | 59°F | 68.8°F | 3.35 | 10 | 3 | <1 | 15 h 20 min |
| July | 83°F | 62°F | 72.8°F | 3.20 | 9 | 4 | <1 | 15 h |
| August | 81°F | 61°F | 71.0°F | 3.46 | 10 | 3 | <1 | 14 h |
| September | 75°F | 53°F | 63.9°F | 2.87 | 10 | 1 | <1 | 12 h 30 min |
| October | 62°F | 43°F | 52.2°F | 3.25 | 11 | <1 | 5 | 11 h 10 min |
| November | 47°F | 33°F | 40.0°F | 2.84 | 11 | <1 | 17 | 9 h 50 min |
| December | 36°F | 24°F | 30.0°F | 1.82 | 11 | <1 | 27 | 9 h |
| Year (annual) | 58°F | 40°F | 49.1°F | 34.00 | 129 | 11 | 144 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −1°C | −8°C | −4.3°C | 53 mm |
| February | 1°C | −7°C | −3.4°C | 46 mm |
| March | 7°C | −3°C | 1.6°C | 49 mm |
| April | 14°C | 2°C | 8.1°C | 91 mm |
| May | 21°C | 9°C | 14.9°C | 97 mm |
| June | 26°C | 15°C | 20.4°C | 85 mm |
| July | 28°C | 17°C | 22.7°C | 81 mm |
| August | 27°C | 16°C | 21.7°C | 88 mm |
| September | 24°C | 12°C | 17.7°C | 73 mm |
| October | 17°C | 6°C | 11.2°C | 83 mm |
| November | 8°C | 0°C | 4.4°C | 72 mm |
| December | 2°C | −4°C | −1.1°C | 46 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Lansing (16 miles away), gets 50 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00207280; 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. Johns?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, July has the fewest days with rain (9).
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 USC00207280.
When is the last frost in St. Johns?
In St. Johns, the last spring frost (32°F) comes after April 28 in half of years and after May 12 in one year in ten; the first autumn frost comes before October 24 in half of years and before October 7 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
- April 281 year in 10 after May 12; 9 in 10 after April 12
- First autumn frost, half of years before
- October 241 year in 10 before October 7; 9 in 10 before November 7
NOAA puts the median frost-free season at 179 days, and the season without a hard freeze (28°F) at 203 days.
A hard freeze (28°F) comes after April 15 in half of springs and before November 5 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts St. Johns in zone 6a in ZIP code 48879, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, St. Johns's NOAA station is in zone 6a: the coldest night of a typical year reaches −6°F (16 complete years).
Frost dates for every NOAA station in Michigan · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00207280; 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. Johns?
In a normal year in St. Johns, 11 days a year reach 90°F, 144 nights fall to 32°F or colder and 129 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
- 144a normal year
- Days that stay below freezing
- 52high of 32°F or less
- Days with 0.01 inch of precipitation
- 129a normal year
The highest temperature in this station's record (since 1894) is 102°F, on July 7, 2012; the lowest is −25°F, on January 21, 1984.
The wettest calendar year on that record is 1950, with 41.50 in; the snowiest season is 2007–08, with 85.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00207280; records: ACIS (NOAA Regional Climate Centers), station USC00207280. Records use complete months only; a month missing more than three days is left out.
How sunny is St. Johns?
Over a year 71% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around St. Johns, 3.8 kWh per square metre a day. July is the sunniest month (81%) and December the cloudiest (53%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 57% | 1.5 |
| February | 63% | 2.4 |
| March | 68% | 3.6 |
| April | 69% | 4.6 |
| May | 71% | 5.5 |
| June | 77% | 6.2 |
| July | 81% | 6.3 |
| August | 78% | 5.3 |
| September | 76% | 4.2 |
| October | 66% | 2.6 |
| November | 61% | 1.6 |
| December | 53% | 1.1 |
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. Johns need?
A normal year in St. Johns brings 6,508 heating degree days, 21% more than the median U.S. place (5,373), and 745 cooling degree days, 18% 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 2,891 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,266 | 0 |
| February | 1,097 | 0 |
| March | 934 | 1 |
| April | 554 | 4 |
| May | 240 | 46 |
| June | 44 | 158 |
| July | 7 | 247 |
| August | 14 | 200 |
| September | 111 | 80 |
| October | 408 | 10 |
| November | 748 | 0 |
| December | 1,083 | 0 |
| Year (annual) | 6,508 | 745 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00207280. 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.
How does St. Johns's climate compare?
St. Johns is warmer than 121 of the other 139 places with their own NOAA record in Michigan, and wetter than 57. Across the 7,247 U.S. stations with normals, its annual mean of 49.1°F is warmer than 36%.
In the Köppen classification computed from these normals, St. Johns is Dfa: continental, no dry season, hot 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. Johns share this climate record?
9 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.
- Ovid, MI1,489 people · 9 mi E
- Fowler, MI1,234 people · 10 mi W
- Lake Victoria, MI1,002 people · 11 mi SE
- Elsie, MI947 people · 10 mi NE
- Westphalia, MI943 people · 13 mi SW
- Maple Rapids, MI583 people · 9 mi NW
- Ashley, MI512 people · 13 mi N
- Perrinton, MI392 people · 13 mi NW
- Eureka, MI91 people · 7 mi N
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. Johns's climate
What is the coldest month in St. Johns?
January, with a normal high of 31°F and a normal low of 18°F. The warmest is July (83°F by day, 62°F at night).
Does it snow in St. Johns?
Yes. NOAA publishes no 1991-2020 snowfall normal for St. Johns's NOAA station; the nearest record that keeps one, Lansing (16 miles away), records 50 inches of snow in a normal year.
What is the rainiest month in St. Johns?
May, with 3.83 in of precipitation in a normal year; the driest is February with 1.80 in.
What plant hardiness zone is St. Johns in?
The USDA's 2023 map puts St. Johns in zone 6a in ZIP code 48879, the nearest ZIP area. By the same method at St. Johns's NOAA station, the coldest night of a typical year reaches −6°F (16 years, 1991-2020): zone 6a.
How late can frost come in St. Johns?
In half of years the last 32°F night comes after April 28; in one year in ten it comes after May 12. Waiting until May 12 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Michigan climateThe statewide normals and every place in the state
- Lansing, MI16 miles from this station, 48.6°F a year
- Owosso, MI19 miles from this station, 47.6°F a year
- East Lansing, MI24 miles from this station, 49.2°F a year
- Corunna, MI24 miles from this station, 47.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made