Oelwein, Iowa climate: Normal weather by month, frost dates and records
Oelwein's normal year runs from 7°F January nights to 82°F July afternoons. (NOAA 1991-2020 normals)
In metric: a yearly mean of 7.9°C, January lows of −14°C, July highs of 28°C.
- NOAA stationOelwein (2 mi S)
- Station IDUSC00136200
- Location42.65°N 91.91°W
- Elevation1,010 ft (308 m)
- From the center2 miles
- Population5,788
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Oelwein.
- Jan 26° 7°
- Feb 29° 10°
- Mar 43° 24°
- Apr 58° 37°
- May 69° 48°
- Jun 79° 59°
- Jul 82° 62°
- Aug 79° 60°
- Sep 74° 51°
- Oct 60° 38°
- Nov 44° 25°
- Dec 31° 15°
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 Oelwein each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 7°F.
| Month | High | Low | Mean | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|
| January | 26°F | 7°F | 16.2°F | – | <1 | 31 | 9 h 20 min |
| February | 29°F | 10°F | 19.3°F | – | <1 | 26 | 10 h 30 min |
| March | 43°F | 24°F | 33.5°F | – | <1 | 25 | 11 h 50 min |
| April | 58°F | 37°F | 47.2°F | – | <1 | 10 | 13 h 20 min |
| May | 69°F | 48°F | 58.6°F | – | <1 | 1 | 14 h 40 min |
| June | 79°F | 59°F | 69.2°F | – | 2 | <1 | 15 h 20 min |
| July | 82°F | 62°F | 71.9°F | – | 2 | <1 | 15 h |
| August | 79°F | 60°F | 69.8°F | – | 2 | <1 | 14 h |
| September | 74°F | 51°F | 62.6°F | – | 1 | 1 | 12 h 30 min |
| October | 60°F | 38°F | 49.2°F | – | <1 | 8 | 11 h 10 min |
| November | 44°F | 25°F | 34.7°F | – | <1 | 22 | 9 h 50 min |
| December | 31°F | 15°F | 23.0°F | – | <1 | 29 | 9 h |
| Year (annual) | 56°F | 36°F | 46.3°F | – | 7 | 153 |
The same normals in °C and millimetres
| Month | High | Low | Mean |
|---|---|---|---|
| January | −4°C | −14°C | −8.8°C |
| February | −2°C | −12°C | −7.1°C |
| March | 6°C | −4°C | 0.8°C |
| April | 14°C | 3°C | 8.4°C |
| May | 21°C | 9°C | 14.8°C |
| June | 26°C | 15°C | 20.7°C |
| July | 28°C | 17°C | 22.2°C |
| August | 26°C | 16°C | 21.0°C |
| September | 23°C | 11°C | 17.0°C |
| October | 16°C | 3°C | 9.6°C |
| November | 7°C | −4°C | 1.5°C |
| December | 0°C | −10°C | −5.0°C |
NOAA publishes no 1991-2020 snowfall normal for this station. Oelwein's own co-op station Oelwein (1 mi E) does: 39 inches of snow in a normal year (see the other stations below).
Source: NOAA NCEI 1991-2020 monthly normals, station USC00136200; 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 Oelwein?
Normal highs sit between 65°F and 85°F in May, June, July, August and September.
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 USC00136200.
When is the last frost in Oelwein?
In Oelwein, the last spring frost (32°F) comes after April 30 in half of years and after May 13 in one year in ten; the first autumn frost comes before October 9 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 13; 9 in 10 after April 14
- First autumn frost, half of years before
- October 91 year in 10 before September 26; 9 in 10 before October 20
NOAA puts the median frost-free season at 163 days, and the season without a hard freeze (28°F) at 182 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 Oelwein in zone 5a in ZIP code 50662, the nearest ZIP area.
Frost dates for every NOAA station in Iowa · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00136200; 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 Oelwein?
In a normal year in Oelwein, 7 days a year reach 90°F and 153 nights fall to 32°F or colder.
- 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
- 153a normal year
- Days that stay below freezing
- 64high of 32°F or less
The highest temperature in this station's record (since 1923) is 109°F, on July 14, 1936; the lowest is −32°F, on January 8, 1942.
The wettest calendar year on that record is 1961, with 48.46 in; the snowiest season is 1961–62, with 77.3 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00136200; records: ACIS (NOAA Regional Climate Centers), station USC00136200. Records use complete months only; a month missing more than three days is left out.
How sunny is Oelwein?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Oelwein, 4.0 kWh per square metre a day. July is the sunniest month (80%) and December the cloudiest (63%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 67% | 1.8 |
| February | 72% | 2.9 |
| March | 70% | 3.8 |
| April | 68% | 4.7 |
| May | 71% | 5.6 |
| June | 75% | 6.2 |
| July | 80% | 6.3 |
| August | 80% | 5.5 |
| September | 79% | 4.4 |
| October | 70% | 2.9 |
| November | 69% | 2.0 |
| December | 63% | 1.5 |
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 Oelwein need?
A normal year in Oelwein brings 7,448 heating degree days, 39% more than the median U.S. place (5,373), and 663 cooling degree days, 27% 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 2,750 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,512 | 0 |
| February | 1,278 | 0 |
| March | 975 | 0 |
| April | 539 | 4 |
| May | 234 | 36 |
| June | 35 | 159 |
| July | 8 | 221 |
| August | 18 | 165 |
| September | 142 | 69 |
| October | 498 | 8 |
| November | 909 | 0 |
| December | 1,300 | 0 |
| Year (annual) | 7,448 | 663 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00136200. 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 Oelwein's climate compare?
Oelwein is warmer than 25 of the other 131 places with their own NOAA record in Iowa. Across the 7,247 U.S. stations with normals, its annual mean of 46.3°F is warmer than 25%.
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers.
Which places near Oelwein 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.
- Fairbank, IA1,133 people · 7 mi W
- Hazleton, IA711 people · 2 mi S
- Westgate, IA190 people · 9 mi NW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
What do Oelwein's other NOAA stations record?
One more NOAA station keeps 1991-2020 normals in or near Oelwein. This page uses Oelwein (2 mi S); the other differs by site and elevation:
| Station | From the center | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Oelwein (1 mi E) USC00136199 | 2 mi E | 1,165 ft | 47.6°F | 9°F | 83°F | 35.4 | 39 | April 27 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Oelwein's climate
What is the coldest month in Oelwein?
January, with a normal high of 26°F and a normal low of 7°F. The warmest is July (82°F by day, 62°F at night).
Does it snow in Oelwein?
Yes. NOAA publishes no 1991-2020 snowfall normal for Oelwein's NOAA station; Oelwein's own co-op station Oelwein (1 mi E) records 39 inches of snow in a normal year.
What plant hardiness zone is Oelwein in?
The USDA's 2023 map puts Oelwein in zone 5a in ZIP code 50662, the nearest ZIP area.
How late can frost come in Oelwein?
In half of years the last 32°F night comes after April 30; in one year in ten it comes after May 13. Waiting until May 13 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Iowa climateThe statewide normals and every place in the state
- Stanley, IA2 miles from this station, 45.4°F a year
- Independence, IA9 miles from this station, 47.0°F a year
- Fayette, IA17 miles from this station, 45.0°F a year
- Tripoli, IA21 miles from this station, 46.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made