Unionville, Missouri climate: Normal weather by month, frost dates and records
Unionville's normal year runs from 15°F January nights to 86°F July afternoons, with 41.9 inches of precipitation and 29 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.5°C, January lows of −10°C, July highs of 30°C, 1,065 mm of precipitation a year.
- NOAA stationUnionville
- Station IDUSC00238523
- Location40.48°N 93.00°W
- Elevation1,060 ft (323 m)
- Population1,668
On October 22, the normal high in Unionville is 61°F and the normal low 40°F, and the chance of measurable rain or snow is 25%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Unionville.
- Jan 32° 15°
- Feb 38° 18°
- Mar 50° 29°
- Apr 62° 39°
- May 71° 52°
- Jun 81° 61°
- Jul 86° 66°
- Aug 84° 64°
- Sep 76° 55°
- Oct 64° 43°
- Nov 50° 30°
- Dec 37° 20°
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 Unionville each month?
July is the warmest month, with normal highs of 86°F; January the coldest, with normal lows of 15°F. The most precipitation falls in May (6.04 in), the least in January (1.35 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 32°F | 15°F | 23.5°F | 1.35 | 6.0 | 6 | <1 | 30 | 9 h 30 min |
| February | 38°F | 18°F | 27.8°F | 1.69 | 9.9 | 7 | <1 | 26 | 10 h 40 min |
| March | 50°F | 29°F | 39.4°F | 2.60 | 3.0 | 8 | <1 | 20 | 11 h 50 min |
| April | 62°F | 39°F | 50.6°F | 3.80 | 1.2 | 10 | <1 | 7 | 13 h 10 min |
| May | 71°F | 52°F | 61.6°F | 6.04 | 0.4 | 12 | <1 | <1 | 14 h 20 min |
| June | 81°F | 61°F | 71.2°F | 5.62 | 0.0 | 10 | 3 | <1 | 15 h |
| July | 86°F | 66°F | 75.5°F | 4.64 | 0.0 | 9 | 8 | <1 | 14 h 50 min |
| August | 84°F | 64°F | 73.6°F | 5.29 | 0.0 | 9 | 6 | <1 | 13 h 50 min |
| September | 76°F | 55°F | 65.5°F | 3.52 | 0.0 | 8 | 1 | <1 | 12 h 30 min |
| October | 64°F | 43°F | 53.1°F | 3.15 | 0.5 | 9 | <1 | 5 | 11 h 10 min |
| November | 50°F | 30°F | 39.8°F | 2.32 | 1.9 | 7 | <1 | 17 | 10 h |
| December | 37°F | 20°F | 28.7°F | 1.91 | 5.8 | 7 | <1 | 28 | 9 h 20 min |
| Year (annual) | 61°F | 41°F | 50.9°F | 41.93 | 28.7 | 102 | 20 | 134 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 0°C | −10°C | −4.7°C | 34 mm | 15 cm |
| February | 3°C | −8°C | −2.3°C | 43 mm | 25 cm |
| March | 10°C | −2°C | 4.1°C | 66 mm | 8 cm |
| April | 17°C | 4°C | 10.3°C | 97 mm | 3 cm |
| May | 22°C | 11°C | 16.4°C | 153 mm | 1 cm |
| June | 27°C | 16°C | 21.8°C | 143 mm | 0 cm |
| July | 30°C | 19°C | 24.2°C | 118 mm | 0 cm |
| August | 29°C | 18°C | 23.1°C | 134 mm | 0 cm |
| September | 25°C | 13°C | 18.6°C | 89 mm | 0 cm |
| October | 18°C | 6°C | 11.7°C | 80 mm | 1 cm |
| November | 10°C | −1°C | 4.3°C | 59 mm | 5 cm |
| December | 3°C | −6°C | −1.8°C | 49 mm | 15 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00238523; 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 Unionville?
Normal highs sit between 65°F and 85°F in May, June, August and September. Of those, September has the fewest days with rain (8).
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 USC00238523.
When is the last frost in Unionville?
In Unionville, the last spring frost (32°F) comes after April 17 in half of years and after April 30 in one year in ten; the first autumn frost comes before October 22 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 171 year in 10 after April 30; 9 in 10 after April 4
- First autumn frost, half of years before
- October 221 year in 10 before October 7; 9 in 10 before November 1
NOAA puts the median frost-free season at 186 days, and the season without a hard freeze (28°F) at 205 days.
A hard freeze (28°F) comes after April 8 in half of springs and before October 31 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Unionville in zone 5b in ZIP code 63565, the nearest ZIP area.
Frost dates for every NOAA station in Missouri · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00238523; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. 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 Unionville?
In a normal year in Unionville, 20 days a year reach 90°F (1 of them 100°F or more), 134 nights fall to 32°F or colder and 102 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
- 134a normal year
- Days that stay below freezing
- 41high of 32°F or less
- Days with 0.01 inch of precipitation
- 102a normal year
- Days with 1 inch of snow or more
- 9a normal year
The highest temperature in this station's record (since 1893) is 114°F, on August 9, 1934; the lowest is −29°F, on December 24, 1989.
The wettest calendar year on that record is 2008, with 74.07 in; the snowiest season is 1961–62, with 65.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00238523; records: ACIS (NOAA Regional Climate Centers), station USC00238523. Records use complete months only; a month missing more than three days is left out.
How sunny is Unionville?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Unionville, 4.1 kWh per square metre a day. July is the sunniest month (82%) and January the cloudiest (66%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 66% | 2.0 |
| February | 70% | 2.9 |
| March | 68% | 3.8 |
| April | 70% | 4.9 |
| May | 72% | 5.7 |
| June | 78% | 6.4 |
| July | 82% | 6.4 |
| August | 80% | 5.6 |
| September | 81% | 4.7 |
| October | 74% | 3.2 |
| November | 72% | 2.3 |
| December | 68% | 1.8 |
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 Unionville need?
A normal year in Unionville brings 6,103 heating degree days, 14% more than the median U.S. place (5,373), and 986 cooling degree days, 9% more 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 3,365 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,288 | 0 |
| February | 1,042 | 0 |
| March | 795 | 1 |
| April | 439 | 5 |
| May | 164 | 58 |
| June | 14 | 199 |
| July | 2 | 329 |
| August | 7 | 275 |
| September | 91 | 104 |
| October | 384 | 15 |
| November | 755 | 0 |
| December | 1,124 | 0 |
| Year (annual) | 6,103 | 986 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00238523. 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 Unionville been warmer than normal lately?
Over 79 complete years from 1900 to 2017, the station's annual mean temperature rose at a fitted 1.4°F per century (+0.08°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 Unionville's climate compare?
Unionville is warmer than 3 of the other 133 places with their own NOAA record in Missouri, and wetter than 43. Across the 7,247 U.S. stations with normals, its annual mean of 50.9°F is warmer than 44%.
In the Köppen classification computed from these normals, Unionville 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 Unionville share this climate record?
5 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.
- Seymour, IA646 people · 16 mi NW
- Cincinnati, IA280 people · 12 mi N
- Exline, IA157 people · 15 mi NE
- Promise City, IA91 people · 20 mi N
- Numa, IA69 people · 15 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 Unionville's climate
What is the coldest month in Unionville?
January, with a normal high of 32°F and a normal low of 15°F. The warmest is July (86°F by day, 66°F at night).
Does it snow in Unionville?
Yes: 29 inches in a normal year, falling on 13 days with 0.1 inch or more, the most in February (9.9 inches).
What is the rainiest month in Unionville?
May, with 6.04 in of precipitation in a normal year; the driest is January with 1.35 in.
What plant hardiness zone is Unionville in?
The USDA's 2023 map puts Unionville in zone 5b in ZIP code 63565, the nearest ZIP area.
How late can frost come in Unionville?
In half of years the last 32°F night comes after April 17; in one year in ten it comes after April 30. Waiting until April 30 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Missouri climateThe statewide normals and every place in the state
- Green City, MO9 miles from this station, 49.8°F a year
- Centerville, IA19 miles from this station, 49.9°F a year
- Rathbun, IA25 miles from this station, 50.4°F a year
- Allerton, IA25 miles from this station, 49.8°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made