Rockwell City, Iowa climate: Normal weather by month, frost dates and records
Rockwell City's normal year runs from 8°F January nights to 83°F July afternoons, with 33.8 inches of precipitation and 32 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.4°C, January lows of −13°C, July highs of 28°C, 857 mm of precipitation a year.
- NOAA stationRockwell City
- Station IDUSC00137161
- Location42.40°N 94.63°W
- Elevation1,214 ft (370 m)
- From the centerunder 1 mile
- Population2,185
On October 23, the normal high in Rockwell City is 59°F and the normal low 36°F, and the chance of measurable rain or snow is 23%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Rockwell City.
- Jan 27° 8°
- Feb 31° 12°
- Mar 45° 24°
- Apr 59° 36°
- May 70° 49°
- Jun 80° 60°
- Jul 83° 63°
- Aug 81° 61°
- Sep 75° 51°
- Oct 62° 38°
- Nov 46° 25°
- Dec 32° 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 Rockwell City each month?
July is the warmest month, with normal highs of 83°F; January the coldest, with normal lows of 8°F. The most precipitation falls in June (5.04 in), the least in January (0.76 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 27°F | 8°F | 17.4°F | 0.76 | 7.4 | 5 | <1 | 31 | 9 h 20 min |
| February | 31°F | 12°F | 21.8°F | 0.99 | 7.6 | 5 | <1 | 27 | 10 h 30 min |
| March | 45°F | 24°F | 34.7°F | 1.99 | 4.9 | 7 | <1 | 24 | 11 h 50 min |
| April | 59°F | 36°F | 47.4°F | 3.76 | 1.9 | 9 | <1 | 10 | 13 h 20 min |
| May | 70°F | 49°F | 59.4°F | 5.02 | 0.0 | 12 | 1 | 1 | 14 h 30 min |
| June | 80°F | 60°F | 69.6°F | 5.04 | 0.0 | 11 | 3 | <1 | 15 h 20 min |
| July | 83°F | 63°F | 72.9°F | 3.54 | 0.0 | 9 | 5 | <1 | 15 h |
| August | 81°F | 61°F | 70.6°F | 4.53 | 0.0 | 9 | 3 | <1 | 14 h |
| September | 75°F | 51°F | 63.0°F | 2.95 | 0.0 | 8 | 2 | <1 | 12 h 30 min |
| October | 62°F | 38°F | 50.3°F | 2.35 | 0.6 | 8 | <1 | 8 | 11 h 10 min |
| November | 46°F | 25°F | 35.6°F | 1.48 | 2.4 | 5 | <1 | 23 | 9 h 50 min |
| December | 32°F | 15°F | 23.4°F | 1.34 | 7.3 | 5 | <1 | 30 | 9 h 10 min |
| Year (annual) | 58°F | 37°F | 47.2°F | 33.75 | 32.1 | 94 | 13 | 154 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −3°C | −13°C | −8.1°C | 19 mm | 19 cm |
| February | 0°C | −11°C | −5.7°C | 25 mm | 19 cm |
| March | 7°C | −4°C | 1.5°C | 51 mm | 12 cm |
| April | 15°C | 2°C | 8.6°C | 96 mm | 5 cm |
| May | 21°C | 9°C | 15.2°C | 128 mm | 0 cm |
| June | 26°C | 15°C | 20.9°C | 128 mm | 0 cm |
| July | 28°C | 17°C | 22.7°C | 90 mm | 0 cm |
| August | 27°C | 16°C | 21.4°C | 115 mm | 0 cm |
| September | 24°C | 11°C | 17.2°C | 75 mm | 0 cm |
| October | 17°C | 4°C | 10.2°C | 60 mm | 2 cm |
| November | 8°C | −4°C | 2.0°C | 38 mm | 6 cm |
| December | 0°C | −10°C | −4.8°C | 34 mm | 19 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00137161; 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 Rockwell City?
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 (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 USC00137161.
When is the last frost in Rockwell City?
In Rockwell City, the last spring frost (32°F) comes after April 26 in half of years and after May 6 in one year in ten; the first autumn frost comes before October 10 in half of years and before September 27 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 261 year in 10 after May 6; 9 in 10 after April 11
- First autumn frost, half of years before
- October 101 year in 10 before September 27; 9 in 10 before October 24
NOAA puts the median frost-free season at 167 days, and the season without a hard freeze (28°F) at 188 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 Rockwell City in zone 5a in ZIP code 50579, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Rockwell City's NOAA station is in zone 5a: the coldest night of a typical year reaches −17°F (25 complete years).
Frost dates for every NOAA station in Iowa · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00137161; 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 Rockwell City?
In a normal year in Rockwell City, 13 days a year reach 90°F, 154 nights fall to 32°F or colder and 94 days bring measurable precipitation.
- Days at 90°F or more
- 13a 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
- 61high of 32°F or less
- Days with 0.01 inch of precipitation
- 94a normal year
- Days with 1 inch of snow or more
- 13a normal year
The highest temperature in this station's record (since 1894) is 110°F, on August 18, 1936; the lowest is −35°F, on January 12, 1912.
The wettest calendar year on that record is 1908, with 49.98 in; the snowiest season is 1961–62, with 66.9 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00137161; records: ACIS (NOAA Regional Climate Centers), station USC00137161. Records use complete months only; a month missing more than three days is left out.
How sunny is Rockwell City?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Rockwell City, 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 Rockwell City need?
A normal year in Rockwell City brings 7,187 heating degree days, 34% more than the median U.S. place (5,373), and 733 cooling degree days, 19% 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 2,888 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,474 | 0 |
| February | 1,208 | 0 |
| March | 938 | 0 |
| April | 532 | 4 |
| May | 218 | 43 |
| June | 30 | 166 |
| July | 6 | 250 |
| August | 15 | 188 |
| September | 131 | 73 |
| October | 464 | 8 |
| November | 882 | 0 |
| December | 1,290 | 0 |
| Year (annual) | 7,187 | 733 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00137161. 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 Rockwell City been warmer than normal lately?
2022 averaged 45.9°F, 1.3°F below the 1991-2020 normal of 47.2°F. 1 of the 2 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 49.2°F | +2.0°F | 31.91 | 33.5 |
| 2022 | 45.9°F | −1.3°F | 22.44 | 26.7 |
Over 94 complete years from 1898 to 2022, 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 USC00137161; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Rockwell City's climate compare?
Rockwell City is warmer than 51 of the other 131 places with their own NOAA record in Iowa, and wetter than 29. Across the 7,247 U.S. stations with normals, its annual mean of 47.2°F is warmer than 29%.
In the Köppen classification computed from these normals, Rockwell 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 Rockwell City share this climate record?
11 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.
- Lake City, IA1,656 people · 10 mi SW
- Manson, IA1,646 people · 10 mi NE
- Gowrie, IA943 people · 19 mi SE
- Twin Lakes, IA535 people · 6 mi N
- Pomeroy, IA511 people · 11 mi N
- Lohrville, IA366 people · 10 mi SE
- Farnhamville, IA364 people · 14 mi SE
- Somers, IA121 people · 10 mi E
- Knierim, IA53 people · 10 mi NE
- Rinard, IA38 people · 8 mi SE
- Jolley, IA28 people · 7 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.
Questions about Rockwell City's climate
What is the coldest month in Rockwell City?
January, with a normal high of 27°F and a normal low of 8°F. The warmest is July (83°F by day, 63°F at night).
Does it snow in Rockwell City?
Yes: 32 inches in a normal year, falling on 16 days with 0.1 inch or more, the most in February (7.6 inches).
What is the rainiest month in Rockwell City?
June, with 5.04 in of precipitation in a normal year; the driest is January with 0.76 in.
What plant hardiness zone is Rockwell City in?
The USDA's 2023 map puts Rockwell City in zone 5a in ZIP code 50579, the nearest ZIP area. By the same method at Rockwell City's NOAA station, the coldest night of a typical year reaches −17°F (25 years, 1991-2020): zone 5a.
How late can frost come in Rockwell City?
In half of years the last 32°F night comes after April 26; in one year in ten it comes after May 6. Waiting until May 6 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Iowa climateThe statewide normals and every place in the state
- Sac City, IA18 miles from this station, 46.6°F a year
- Pocahontas, IA23 miles from this station, 46.9°F a year
- Fort Dodge, IA25 miles from this station, 46.5°F a year
- Carroll, IA25 miles from this station, 48.3°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made