Carroll, Iowa climate: Normal weather by month, frost dates and records
Carroll's normal year runs from 10°F January nights to 84°F July afternoons, with 33.7 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.1°C, January lows of −12°C, July highs of 29°C, 856 mm of precipitation a year.
- NOAA stationCarroll
- Station IDUSC00131233
- Location42.06°N 94.85°W
- Elevation1,240 ft (378 m)
- From the centerunder 1 mile
- Population10,125
On October 23, the normal high in Carroll is 59°F and the normal low 37°F, and the chance of measurable rain or snow is 24%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Carroll.
- Jan 28° 10°
- Feb 33° 14°
- Mar 46° 25°
- Apr 60° 36°
- May 71° 49°
- Jun 81° 60°
- Jul 84° 64°
- Aug 82° 61°
- Sep 76° 52°
- Oct 63° 40°
- Nov 46° 27°
- Dec 33° 16°
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 Carroll each month?
July is the warmest month, with normal highs of 84°F; January the coldest, with normal lows of 10°F. The most precipitation falls in June (5.12 in), the least in January (0.90 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 28°F | 10°F | 19.1°F | 0.90 | 7 | <1 | 31 | 9 h 30 min |
| February | 33°F | 14°F | 23.5°F | 1.11 | 7 | <1 | 27 | 10 h 30 min |
| March | 46°F | 25°F | 35.7°F | 1.87 | 8 | <1 | 24 | 11 h 50 min |
| April | 60°F | 36°F | 48.0°F | 3.35 | 11 | <1 | 10 | 13 h 20 min |
| May | 71°F | 49°F | 60.1°F | 4.49 | 13 | 1 | 1 | 14 h 30 min |
| June | 81°F | 60°F | 70.7°F | 5.12 | 12 | 4 | <1 | 15 h 10 min |
| July | 84°F | 64°F | 74.1°F | 4.36 | 10 | 7 | <1 | 15 h |
| August | 82°F | 61°F | 71.7°F | 4.06 | 10 | 4 | <1 | 14 h |
| September | 76°F | 52°F | 64.0°F | 2.95 | 9 | 2 | 1 | 12 h 30 min |
| October | 63°F | 40°F | 51.2°F | 2.68 | 9 | <1 | 8 | 11 h 10 min |
| November | 46°F | 27°F | 36.6°F | 1.44 | 6 | <1 | 22 | 9 h 50 min |
| December | 33°F | 16°F | 24.6°F | 1.38 | 7 | <1 | 30 | 9 h 10 min |
| Year (annual) | 59°F | 38°F | 48.3°F | 33.71 | 106 | 18 | 153 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −2°C | −12°C | −7.2°C | 23 mm |
| February | 0°C | −10°C | −4.7°C | 28 mm |
| March | 8°C | −4°C | 2.1°C | 47 mm |
| April | 16°C | 2°C | 8.9°C | 85 mm |
| May | 22°C | 10°C | 15.6°C | 114 mm |
| June | 27°C | 16°C | 21.5°C | 130 mm |
| July | 29°C | 18°C | 23.4°C | 111 mm |
| August | 28°C | 16°C | 22.1°C | 103 mm |
| September | 25°C | 11°C | 17.8°C | 75 mm |
| October | 17°C | 4°C | 10.7°C | 68 mm |
| November | 8°C | −3°C | 2.6°C | 37 mm |
| December | 1°C | −9°C | −4.1°C | 35 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Jefferson (24 miles away), gets 32 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00131233; 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 Carroll?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September 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 USC00131233.
When is the last frost in Carroll?
In Carroll, the last spring frost (32°F) comes after April 27 in half of years and after May 8 in one year in ten; the first autumn frost comes before October 10 in half of years and before September 25 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 271 year in 10 after May 8; 9 in 10 after April 14
- First autumn frost, half of years before
- October 101 year in 10 before September 25; 9 in 10 before October 24
NOAA puts the median frost-free season at 166 days, and the season without a hard freeze (28°F) at 187 days.
A hard freeze (28°F) comes after April 16 in half of springs and before October 21 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Carroll in zone 5a in ZIP code 51401, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Carroll's NOAA station is in zone 5b: the coldest night of a typical year reaches −15°F (26 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 USC00131233; 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 Carroll?
In a normal year in Carroll, 18 days a year reach 90°F, 153 nights fall to 32°F or colder and 106 days bring measurable precipitation.
- Days at 90°F or more
- 18a 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
- 58high of 32°F or less
- Days with 0.01 inch of precipitation
- 106a normal year
The highest temperature in this station's record (since 1893) is 112°F, on July 4, 1936; the lowest is −40°F, on January 12, 1912.
The wettest calendar year on that record is 1973, with 50.51 in; the snowiest season is 1959–60, with 57.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00131233; records: ACIS (NOAA Regional Climate Centers), station USC00131233. Records use complete months only; a month missing more than three days is left out.
How sunny is Carroll?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Carroll, 4.1 kWh per square metre a day. July is the sunniest month (82%) and December the cloudiest (68%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 71% | 2.0 |
| February | 75% | 3.0 |
| March | 70% | 3.8 |
| April | 70% | 4.8 |
| May | 71% | 5.6 |
| June | 76% | 6.3 |
| July | 82% | 6.5 |
| August | 80% | 5.5 |
| September | 79% | 4.4 |
| October | 73% | 3.1 |
| November | 72% | 2.1 |
| December | 68% | 1.6 |
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 Carroll need?
A normal year in Carroll brings 6,921 heating degree days, 29% more than the median U.S. place (5,373), and 866 cooling degree days, 5% 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 3,081 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,423 | 0 |
| February | 1,162 | 0 |
| March | 908 | 1 |
| April | 515 | 5 |
| May | 205 | 55 |
| June | 26 | 195 |
| July | 4 | 286 |
| August | 12 | 220 |
| September | 120 | 91 |
| October | 440 | 13 |
| November | 854 | 0 |
| December | 1,252 | 0 |
| Year (annual) | 6,921 | 866 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00131233. 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 Carroll been warmer than normal lately?
2025 averaged 49.8°F, 1.5°F above the 1991-2020 normal of 48.3°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 50.5°F | +2.2°F | 23.79 |
| 2022 | 47.6°F | −0.7°F | 22.47 |
| 2023 | 50.7°F | +2.4°F | 25.09 |
| 2024 | 51.5°F | +3.2°F | 29.56 |
| 2025 | 49.8°F | +1.5°F | 37.10 |
Over 98 complete years from 1895 to 2025, the station's annual mean temperature rose at a fitted 0.7°F per century (+0.04°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00131233; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Carroll's climate compare?
Carroll is warmer than 73 of the other 131 places with their own NOAA record in Iowa, and wetter than 28. Across the 7,247 U.S. stations with normals, its annual mean of 48.3°F is warmer than 33%.
In the Köppen classification computed from these normals, Carroll 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 Carroll share this climate record?
12 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.
- Manning, IA1,390 people · 15 mi SW
- Coon Rapids, IA1,258 people · 16 mi SE
- Glidden, IA1,140 people · 6 mi E
- Arcadia, IA588 people · 10 mi W
- Breda, IA492 people · 10 mi NW
- Templeton, IA337 people · 11 mi SW
- Halbur, IA268 people · 8 mi SW
- Dedham, IA221 people · 11 mi S
- Lidderdale, IA162 people · 5 mi NE
- Lanesboro, IA112 people · 12 mi NE
- Ralston, IA76 people · 11 mi E
- Willey, IA72 people · 6 mi S
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 Carroll's climate
What is the coldest month in Carroll?
January, with a normal high of 28°F and a normal low of 10°F. The warmest is July (84°F by day, 64°F at night).
Does it snow in Carroll?
Yes. NOAA publishes no 1991-2020 snowfall normal for Carroll's NOAA station; the nearest record that keeps one, Jefferson (24 miles away), records 32 inches of snow in a normal year.
What is the rainiest month in Carroll?
June, with 5.12 in of precipitation in a normal year; the driest is January with 0.90 in.
What plant hardiness zone is Carroll in?
The USDA's 2023 map puts Carroll in zone 5a in ZIP code 51401, the nearest ZIP area. By the same method at Carroll's NOAA station, the coldest night of a typical year reaches −15°F (26 years, 1991-2020): zone 5b.
How late can frost come in Carroll?
In half of years the last 32°F night comes after April 27; in one year in ten it comes after May 8. Waiting until May 8 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Iowa climateThe statewide normals and every place in the state
- Jefferson, IA24 miles from this station, 47.8°F a year
- Denison, IA25 miles from this station, 47.5°F a year
- Audubon, IA25 miles from this station, 47.0°F a year
- Sac City, IA25 miles from this station, 46.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made