Leon, Iowa climate: Normal weather by month, frost dates and records
Leon's normal year runs from 13°F January nights to 86°F July afternoons, with 39.3 inches of precipitation and 29 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.8°C, January lows of −11°C, July highs of 30°C, 999 mm of precipitation a year.
- NOAA stationLeon (6 mi ESE)
- Station IDUSC00134758
- Location40.72°N 93.65°W
- Elevation1,000 ft (305 m)
- From the center6 miles
- Population1,779
On October 23, the normal high in Leon is 61°F and the normal low 37°F, and the chance of measurable rain or snow is 29%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Leon.
- Jan 33° 13°
- Feb 38° 16°
- Mar 50° 27°
- Apr 63° 37°
- May 72° 48°
- Jun 81° 59°
- Jul 86° 63°
- Aug 84° 61°
- Sep 76° 50°
- Oct 64° 39°
- Nov 50° 28°
- Dec 38° 18°
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 Leon each month?
July is the warmest month, with normal highs of 86°F; January the coldest, with normal lows of 13°F. The most precipitation falls in June (5.56 in), the least in January (0.90 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 33°F | 13°F | 22.6°F | 0.90 | 8.0 | 6 | <1 | 30 | 9 h 30 min |
| February | 38°F | 16°F | 26.7°F | 1.51 | 6.0 | 7 | <1 | 26 | 10 h 40 min |
| March | 50°F | 27°F | 38.7°F | 2.29 | 4.9 | 9 | <1 | 23 | 11 h 50 min |
| April | 63°F | 37°F | 49.6°F | 3.80 | 0.1 | 12 | <1 | 11 | 13 h 20 min |
| May | 72°F | 48°F | 60.1°F | 5.54 | 0.0 | 14 | <1 | 1 | 14 h 30 min |
| June | 81°F | 59°F | 69.7°F | 5.56 | 0.0 | 13 | 2 | <1 | 15 h |
| July | 86°F | 63°F | 74.2°F | 4.43 | 0.0 | 11 | 8 | <1 | 14 h 50 min |
| August | 84°F | 61°F | 72.0°F | 4.54 | 0.0 | 10 | 6 | <1 | 13 h 50 min |
| September | 76°F | 50°F | 63.2°F | 4.17 | 0.0 | 8 | 1 | 1 | 12 h 30 min |
| October | 64°F | 39°F | 51.6°F | 3.17 | 0.2 | 9 | <1 | 10 | 11 h 10 min |
| November | 50°F | 28°F | 38.9°F | 2.07 | 1.5 | 7 | <1 | 21 | 10 h |
| December | 38°F | 18°F | 27.8°F | 1.35 | 7.8 | 7 | <1 | 29 | 9 h 20 min |
| Year (annual) | 61°F | 38°F | 49.6°F | 39.33 | 28.5 | 113 | 17 | 150 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 0°C | −11°C | −5.2°C | 23 mm | 20 cm |
| February | 3°C | −9°C | −2.9°C | 38 mm | 15 cm |
| March | 10°C | −3°C | 3.7°C | 58 mm | 12 cm |
| April | 17°C | 3°C | 9.8°C | 97 mm | 0 cm |
| May | 22°C | 9°C | 15.6°C | 141 mm | 0 cm |
| June | 27°C | 15°C | 20.9°C | 141 mm | 0 cm |
| July | 30°C | 17°C | 23.4°C | 113 mm | 0 cm |
| August | 29°C | 16°C | 22.2°C | 115 mm | 0 cm |
| September | 24°C | 10°C | 17.3°C | 106 mm | 0 cm |
| October | 18°C | 4°C | 10.9°C | 81 mm | 1 cm |
| November | 10°C | −2°C | 3.8°C | 53 mm | 4 cm |
| December | 3°C | −8°C | −2.3°C | 34 mm | 20 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00134758; 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 Leon?
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 USC00134758.
When is the last frost in Leon?
In Leon, the last spring frost (32°F) comes after April 30 in half of years and after May 15 in one year in ten; the first autumn frost comes before October 8 in half of years and before September 26 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 301 year in 10 after May 15; 9 in 10 after April 16
- First autumn frost, half of years before
- October 81 year in 10 before September 26; 9 in 10 before October 22
NOAA puts the median frost-free season at 161 days, and the season without a hard freeze (28°F) at 183 days.
A hard freeze (28°F) comes after April 19 in half of springs and before October 19 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Leon in zone 5b in ZIP code 50144, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Leon's NOAA station is in zone 5a: the coldest night of a typical year reaches −15°F (18 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 Iowa · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00134758; 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 Leon?
In a normal year in Leon, 17 days a year reach 90°F (1 of them 100°F or more), 150 nights fall to 32°F or colder and 113 days bring measurable precipitation.
- Days at 90°F or more
- 17a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 150a normal year
- Days that stay below freezing
- 41high of 32°F or less
- Days with 0.01 inch of precipitation
- 113a normal year
- Days with 1 inch of snow or more
- 9a normal year
The highest temperature in this station's record (since 1902) is 109°F, on July 5, 1911; the lowest is −33°F, on December 24, 1989.
The wettest calendar year on that record is 1973, with 52.66 in; the snowiest season is 2007–08, with 63.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00134758; records: ACIS (NOAA Regional Climate Centers), station USC00134758. Records use complete months only; a month missing more than three days is left out.
How sunny is Leon?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Leon, 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 Leon need?
A normal year in Leon brings 6,406 heating degree days, 19% more than the median U.S. place (5,373), and 823 cooling degree days, 9% 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 3,078 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,313 | 0 |
| February | 1,074 | 0 |
| March | 817 | 2 |
| April | 466 | 6 |
| May | 200 | 48 |
| June | 29 | 169 |
| July | 3 | 287 |
| August | 11 | 229 |
| September | 127 | 73 |
| October | 428 | 11 |
| November | 785 | 0 |
| December | 1,155 | 0 |
| Year (annual) | 6,406 | 823 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00134758. 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 Leon's climate compare?
Leon is warmer than 99 of the other 131 places with their own NOAA record in Iowa, and wetter than 119. Across the 7,247 U.S. stations with normals, its annual mean of 49.6°F is warmer than 38%.
In the Köppen classification computed from these normals, Leon 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 Leon share this climate record?
3 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.
- Humeston, IA472 people · 12 mi NE
- Garden Grove, IA173 people · 7 mi N
- Le Roy, IA10 people · 11 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 Leon's climate
What is the coldest month in Leon?
January, with a normal high of 33°F and a normal low of 13°F. The warmest is July (86°F by day, 63°F at night).
Does it snow in Leon?
Yes: 29 inches in a normal year, falling on 18 days with 0.1 inch or more, the most in January (8.0 inches).
What is the rainiest month in Leon?
June, with 5.56 in of precipitation in a normal year; the driest is January with 0.90 in.
What plant hardiness zone is Leon in?
The USDA's 2023 map puts Leon in zone 5b in ZIP code 50144, the nearest ZIP area. By the same method at Leon's NOAA station, the coldest night of a typical year reaches −15°F (18 years, 1991-2020): zone 5a.
How late can frost come in Leon?
In half of years the last 32°F night comes after April 30; in one year in ten it comes after May 15. Waiting until May 15 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Iowa climateThe statewide normals and every place in the state
- Allerton, IA14 miles from this station, 49.8°F a year
- Lamoni, IA15 miles from this station, 51.6°F a year
- Osceola, IA21 miles from this station, 49.8°F a year
- Beaconsfield, IA22 miles from this station, 49.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made