Ionia, Michigan climate: Normal weather by month, frost dates and records
Ionia's normal year runs from 16°F January nights to 81°F July afternoons, with 35.9 inches of precipitation and 54 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.4°C, January lows of −9°C, July highs of 27°C, 912 mm of precipitation a year.
- NOAA stationIonia (2 mi SSW)
- Station IDUSC00204078
- Location42.95°N 85.08°W
- Elevation805 ft (245 m)
- From the center2 miles
- Population12,265
On October 23, the normal high in Ionia is 56°F and the normal low 38°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 Ionia.
- Jan 29° 16°
- Feb 32° 16°
- Mar 42° 24°
- Apr 56° 35°
- May 68° 47°
- Jun 77° 57°
- Jul 81° 60°
- Aug 79° 59°
- Sep 72° 51°
- Oct 59° 40°
- Nov 46° 30°
- Dec 34° 22°
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 Ionia each month?
July is the warmest month, with normal highs of 81°F; January the coldest, with normal lows of 16°F. The most precipitation falls in May (3.97 in), the least in February (1.71 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 29°F | 16°F | 22.3°F | 2.20 | 15.5 | 14 | <1 | 29 | 9 h 20 min |
| February | 32°F | 16°F | 24.0°F | 1.71 | 11.9 | 12 | <1 | 27 | 10 h 30 min |
| March | 42°F | 24°F | 33.3°F | 2.23 | 7.0 | 10 | <1 | 25 | 11 h 50 min |
| April | 56°F | 35°F | 45.2°F | 3.28 | 1.6 | 12 | <1 | 13 | 13 h 20 min |
| May | 68°F | 47°F | 57.4°F | 3.97 | 0.0 | 12 | <1 | 2 | 14 h 40 min |
| June | 77°F | 57°F | 67.0°F | 3.88 | 0.0 | 10 | 2 | <1 | 15 h 20 min |
| July | 81°F | 60°F | 70.6°F | 3.37 | 0.0 | 10 | 3 | <1 | 15 h |
| August | 79°F | 59°F | 68.8°F | 3.69 | 0.0 | 10 | 1 | <1 | 14 h |
| September | 72°F | 51°F | 61.3°F | 3.03 | 0.0 | 10 | <1 | <1 | 12 h 30 min |
| October | 59°F | 40°F | 49.4°F | 3.55 | 0.5 | 11 | <1 | 7 | 11 h 10 min |
| November | 46°F | 30°F | 37.9°F | 2.79 | 3.6 | 12 | <1 | 18 | 9 h 50 min |
| December | 34°F | 22°F | 28.0°F | 2.22 | 14.1 | 14 | <1 | 28 | 9 h |
| Year (annual) | 56°F | 38°F | 47.1°F | 35.92 | 54.2 | 138 | 7 | 148 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −2°C | −9°C | −5.4°C | 56 mm | 39 cm |
| February | 0°C | −9°C | −4.4°C | 43 mm | 30 cm |
| March | 6°C | −4°C | 0.7°C | 57 mm | 18 cm |
| April | 13°C | 2°C | 7.3°C | 83 mm | 4 cm |
| May | 20°C | 8°C | 14.1°C | 101 mm | 0 cm |
| June | 25°C | 14°C | 19.4°C | 99 mm | 0 cm |
| July | 27°C | 16°C | 21.4°C | 86 mm | 0 cm |
| August | 26°C | 15°C | 20.4°C | 94 mm | 0 cm |
| September | 22°C | 10°C | 16.3°C | 77 mm | 0 cm |
| October | 15°C | 4°C | 9.7°C | 90 mm | 1 cm |
| November | 8°C | −1°C | 3.3°C | 71 mm | 9 cm |
| December | 1°C | −6°C | −2.2°C | 56 mm | 36 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00204078; 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 Ionia?
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 (10).
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 USC00204078.
When is the last frost in Ionia?
In Ionia, the last spring frost (32°F) comes after May 3 in half of years and after May 21 in one year in ten; the first autumn frost comes before October 12 in half of years and before September 29 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 21; 9 in 10 after April 17
- First autumn frost, half of years before
- October 121 year in 10 before September 29; 9 in 10 before October 27
NOAA puts the median frost-free season at 161 days, and the season without a hard freeze (28°F) at 186 days.
A hard freeze (28°F) comes after April 22 in half of springs and before October 27 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Ionia in zone 6a in ZIP code 48846, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Ionia's NOAA station is in zone 6a: the coldest night of a typical year reaches −7°F (21 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 USC00204078; 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 Ionia?
In a normal year in Ionia, 7 days a year reach 90°F, 148 nights fall to 32°F or colder and 138 days bring measurable precipitation.
- Days at 90°F or more
- 7a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 148a normal year
- Days that stay below freezing
- 57high of 32°F or less
- Days with 0.01 inch of precipitation
- 138a normal year
- Days with 1 inch of snow or more
- 17a normal year
The highest temperature in this station's record (since 1896) is 103°F, on July 6, 1988; the lowest is −25°F, on January 15, 1963.
The wettest calendar year on that record is 1986, with 45.65 in; the snowiest season is 2007–08, with 74.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00204078; records: ACIS (NOAA Regional Climate Centers), station USC00204078. Records use complete months only; a month missing more than three days is left out.
How sunny is Ionia?
Over a year 70% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Ionia, 3.8 kWh per square metre a day. July is the sunniest month (81%) and December the cloudiest (50%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 52% | 1.4 |
| February | 57% | 2.2 |
| March | 65% | 3.5 |
| April | 68% | 4.7 |
| May | 71% | 5.5 |
| June | 77% | 6.3 |
| July | 81% | 6.3 |
| August | 79% | 5.4 |
| September | 77% | 4.3 |
| October | 65% | 2.7 |
| November | 60% | 1.7 |
| December | 50% | 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 Ionia need?
A normal year in Ionia brings 7,039 heating degree days, 31% more than the median U.S. place (5,373), and 546 cooling degree days, 40% 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 2,525 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,325 | 0 |
| February | 1,149 | 0 |
| March | 983 | 1 |
| April | 598 | 3 |
| May | 270 | 33 |
| June | 62 | 122 |
| July | 16 | 189 |
| August | 27 | 145 |
| September | 162 | 50 |
| October | 487 | 5 |
| November | 812 | 0 |
| December | 1,148 | 0 |
| Year (annual) | 7,039 | 546 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00204078. 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 Ionia's climate compare?
Ionia is warmer than 75 of the other 139 places with their own NOAA record in Michigan, and wetter than 96. Across the 7,247 U.S. stations with normals, its annual mean of 47.1°F is warmer than 28%.
In the Köppen classification computed from these normals, Ionia 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 Ionia share this climate record?
10 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.
- Portland, MI3,770 people · 11 mi SE
- Lake Odessa, MI2,065 people · 12 mi S
- Saranac, MI1,379 people · 7 mi W
- Lyons, MI777 people · 7 mi E
- Muir, MI645 people · 8 mi NE
- Sunfield, MI542 people · 14 mi S
- Pewamo, MI517 people · 12 mi E
- Palo, MI409 people · 12 mi NE
- Clarksville, MI401 people · 11 mi SW
- Hubbardston, MI344 people · 15 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 Ionia's climate
What is the coldest month in Ionia?
January, with a normal high of 29°F and a normal low of 16°F. The warmest is July (81°F by day, 60°F at night).
Does it snow in Ionia?
Yes: 54 inches in a normal year, falling on 49 days with 0.1 inch or more, the most in January (15.5 inches).
What is the rainiest month in Ionia?
May, with 3.97 in of precipitation in a normal year; the driest is February with 1.71 in.
What plant hardiness zone is Ionia in?
The USDA's 2023 map puts Ionia in zone 6a in ZIP code 48846, the nearest ZIP area. By the same method at Ionia's NOAA station, the coldest night of a typical year reaches −7°F (21 years, 1991-2020): zone 6a.
How late can frost come in Ionia?
In half of years the last 32°F night comes after May 3; in one year in ten it comes after May 21. Waiting until May 21 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Michigan climateThe statewide normals and every place in the state
- Greenville, MI19 miles from this station, 46.9°F a year
- Grand Rapids, MI24 miles from this station, 49.3°F a year
- Kentwood, MI24 miles from this station, 48.3°F a year
- Hastings, MI24 miles from this station, 47.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made