Charles City, Iowa climate: Normal weather by month, frost dates and records
Charles City's normal year runs from 9°F January nights to 82°F July afternoons, with 37.7 inches of precipitation and 38 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.1°C, January lows of −13°C, July highs of 28°C, 958 mm of precipitation a year.
- NOAA stationCharles City
- Station IDUSC00131402
- Location43.06°N 92.67°W
- Elevation993 ft (303 m)
- From the centerunder 1 mile
- Population7,081
On October 23, the normal high in Charles City is 57°F and the normal low 36°F, and the chance of measurable rain or snow is 27%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Charles City.
- Jan 25° 9°
- Feb 30° 13°
- Mar 43° 25°
- Apr 58° 37°
- May 70° 49°
- Jun 79° 59°
- Jul 82° 62°
- Aug 80° 60°
- Sep 73° 51°
- Oct 60° 39°
- Nov 44° 26°
- Dec 30° 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 Charles City each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 9°F. The most precipitation falls in June (6.13 in), the least in January (1.01 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 25°F | 9°F | 16.6°F | 1.01 | 9.5 | 8 | <1 | 31 | 9 h 20 min |
| February | 30°F | 13°F | 21.1°F | 1.14 | 9.3 | 7 | <1 | 27 | 10 h 30 min |
| March | 43°F | 25°F | 34.2°F | 1.93 | 5.4 | 9 | <1 | 24 | 11 h 50 min |
| April | 58°F | 37°F | 47.4°F | 3.73 | 2.1 | 10 | <1 | 10 | 13 h 20 min |
| May | 70°F | 49°F | 59.0°F | 5.06 | 0.3 | 13 | 1 | 1 | 14 h 40 min |
| June | 79°F | 59°F | 68.7°F | 6.13 | 0.0 | 12 | 2 | <1 | 15 h 20 min |
| July | 82°F | 62°F | 72.0°F | 4.92 | 0.0 | 10 | 4 | <1 | 15 h |
| August | 80°F | 60°F | 69.6°F | 4.28 | 0.0 | 9 | 2 | <1 | 14 h |
| September | 73°F | 51°F | 62.4°F | 3.82 | 0.0 | 9 | 1 | 1 | 12 h 30 min |
| October | 60°F | 39°F | 49.6°F | 2.58 | 0.1 | 9 | <1 | 9 | 11 h 10 min |
| November | 44°F | 26°F | 35.0°F | 1.74 | 2.8 | 7 | <1 | 22 | 9 h 50 min |
| December | 30°F | 15°F | 22.5°F | 1.38 | 8.0 | 8 | <1 | 30 | 9 h |
| Year (annual) | 56°F | 37°F | 46.5°F | 37.72 | 37.5 | 111 | 9 | 154 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −4°C | −13°C | −8.6°C | 26 mm | 24 cm |
| February | −1°C | −11°C | −6.1°C | 29 mm | 24 cm |
| March | 6°C | −4°C | 1.2°C | 49 mm | 14 cm |
| April | 15°C | 3°C | 8.6°C | 95 mm | 5 cm |
| May | 21°C | 9°C | 15.0°C | 129 mm | 1 cm |
| June | 26°C | 15°C | 20.4°C | 156 mm | 0 cm |
| July | 28°C | 17°C | 22.2°C | 125 mm | 0 cm |
| August | 26°C | 15°C | 20.9°C | 109 mm | 0 cm |
| September | 23°C | 11°C | 16.9°C | 97 mm | 0 cm |
| October | 16°C | 4°C | 9.8°C | 66 mm | 0 cm |
| November | 7°C | −3°C | 1.7°C | 44 mm | 7 cm |
| December | −1°C | −9°C | −5.3°C | 35 mm | 20 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00131402; 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 Charles City?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, August 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 USC00131402.
When is the last frost in Charles City?
In Charles City, the last spring frost (32°F) comes after April 30 in half of years and after May 14 in one year in ten; the first autumn frost comes before October 6 in half of years and before September 21 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 14; 9 in 10 after April 15
- First autumn frost, half of years before
- October 61 year in 10 before September 21; 9 in 10 before October 19
NOAA puts the median frost-free season at 157 days, and the season without a hard freeze (28°F) at 178 days.
A hard freeze (28°F) comes after April 21 in half of springs and before October 17 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Charles City in zone 5a in ZIP code 50616, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Charles City's NOAA station is in zone 4b: the coldest night of a typical year reaches −21°F (28 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 USC00131402; 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 Charles City?
In a normal year in Charles City, 9 days a year reach 90°F, 154 nights fall to 32°F or colder and 111 days bring measurable precipitation.
- Days at 90°F or more
- 9a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 154a normal year
- Days that stay below freezing
- 64high of 32°F or less
- Days with 0.01 inch of precipitation
- 111a normal year
- Days with 1 inch of snow or more
- 13a normal year
The highest temperature in this station's record (since 1893) is 108°F, on July 21, 1901; the lowest is −34°F, on January 12, 1912.
The wettest calendar year on that record is 2018, with 61.37 in; the snowiest season is 1961–62, with 77.1 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00131402; records: ACIS (NOAA Regional Climate Centers), station USC00131402. Records use complete months only; a month missing more than three days is left out.
How sunny is Charles City?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Charles City, 3.9 kWh per square metre a day. July is the sunniest month (81%) and December the cloudiest (63%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 69% | 1.8 |
| February | 75% | 3.0 |
| March | 69% | 3.7 |
| April | 68% | 4.7 |
| May | 70% | 5.5 |
| June | 75% | 6.1 |
| July | 81% | 6.3 |
| August | 79% | 5.4 |
| September | 77% | 4.3 |
| October | 69% | 2.8 |
| November | 68% | 1.9 |
| December | 63% | 1.4 |
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 Charles City need?
A normal year in Charles City brings 7,356 heating degree days, 37% more than the median U.S. place (5,373), and 652 cooling degree days, 28% 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 2,754 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,500 | 0 |
| February | 1,231 | 0 |
| March | 955 | 1 |
| April | 532 | 4 |
| May | 226 | 40 |
| June | 36 | 147 |
| July | 8 | 227 |
| August | 20 | 164 |
| September | 144 | 64 |
| October | 485 | 6 |
| November | 900 | 0 |
| December | 1,319 | 0 |
| Year (annual) | 7,356 | 652 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00131402. 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 Charles City been warmer than normal lately?
2024 averaged 49.6°F, 3.1°F above the 1991-2020 normal of 46.5°F. 3 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 48.3°F | +1.8°F | 35.40 | 29.8 |
| 2022 | 45.1°F | −1.4°F | 30.06 | 37.0 |
| 2023 | 48.8°F | +2.3°F | 20.90 | 26.6 |
| 2024 | 49.6°F | +3.1°F | 38.95 | 20.5 |
Over 124 complete years from 1891 to 2024, the station's annual mean temperature rose at a fitted 1.0°F per century (+0.06°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00131402; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Charles City's climate compare?
Charles City is warmer than 29 of the other 131 places with their own NOAA record in Iowa, and wetter than 86. Across the 7,247 U.S. stations with normals, its annual mean of 46.5°F is warmer than 25%.
In the Köppen classification computed from these normals, Charles City 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 Charles City share this climate record?
7 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.
- Nashua, IA1,515 people · 10 mi SE
- Rockford, IA722 people · 14 mi W
- Floyd, IA297 people · 6 mi NW
- Marble Rock, IA258 people · 12 mi SW
- Colwell, IA52 people · 8 mi NE
- Bassett, IA42 people · 8 mi E
- Roseville, IA12 people · 7 mi W
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 Charles City's climate
What is the coldest month in Charles City?
January, with a normal high of 25°F and a normal low of 9°F. The warmest is July (82°F by day, 62°F at night).
Does it snow in Charles City?
Yes: 38 inches in a normal year, falling on 27 days with 0.1 inch or more, the most in January (9.5 inches).
What is the rainiest month in Charles City?
June, with 6.13 in of precipitation in a normal year; the driest is January with 1.01 in.
What plant hardiness zone is Charles City in?
The USDA's 2023 map puts Charles City in zone 5a in ZIP code 50616, the nearest ZIP area. By the same method at Charles City's NOAA station, the coldest night of a typical year reaches −21°F (28 years, 1991-2020): zone 4b.
How late can frost come in Charles City?
In half of years the last 32°F night comes after April 30; in one year in ten it comes after May 14. Waiting until May 14 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Iowa climateThe statewide normals and every place in the state
- Osage, IA17 miles from this station, 45.3°F a year
- New Hampton, IA18 miles from this station, 44.7°F a year
- Allison, IA22 miles from this station, 46.7°F a year
- Tripoli, IA27 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