Hardly any U.S. towns see harsher January nights than Rockwell
Expect July afternoons of about 82°. Its July afternoons stay fresher than in 78% of U.S. towns. Warming shows here too: 1.1° more than in 1901–2000, led by December. The outdoor season runs from May to September, with highs of 70–82°.
A year in Rockwell at a glance
Each month’s typical high and low, and what it brings.
What stands out about Rockwell’s climate
Compared with towns across the U.S., with Rockwell’s place in Iowa beside it.
What a year in Rockwell feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 161 frost-free days a year
In half of years the last 32° night comes by April 29 and the first by October 7. Frost and day counts come from NOAA’s station at Mason City, IA, 13 miles from the town’s center, at about the same height.
The 2023 USDA map puts Rockwell’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −18°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 44 inches of snow a winter
Snow, measured at Mason City Muni Airport, falls mostly in January. Precipitation (rain plus melted snow) adds up to 36 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 116 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Rockwell
93% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Mason City, IA.
Living with Rockwell’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
161 frost-free days in zone 5a. The last frost comes by Apr 29 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 7.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 0.1 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Rockwell from natural hazards, drought is the largest share (42%); heat waves, cold waves, winter storms and ice storms together are 11%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Rockwell and similar climates
TownRatings has no climate map of the towns around Rockwell yet.
Climates most like Rockwell’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Rockwell, IA | 8° | 82° | 36" | 44" |
| Reedsburg, WI | 9° | 82° | 37" | 44" |
| Colchester, VT | 10° | 81° | 38" | 50" |
| Plattsburgh, NY | 9° | 81° | 35" | 50" |
| Hugo, MN | 6° | 82° | 33" | 40" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Rockwell averaged 1.1° warmer than the 1900s. The biggest change is in December (+2.9°).
A smaller shift than in 71% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Rockwell compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Rockwell’s place among Iowa’s.
Rockwell weather by month
Highs, lows and precipitation from NOAA’s grid at Rockwell’s center; snow, wet days and snow on the ground from Mason City Muni Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 24° | 8° | 0.9" | 11.3" | 8 | 24 | 5° – 29° |
| February | 29° | 13° | 1.1" | 10.0" | 8 | 22 | 10° – 32° |
| March | 43° | 25° | 2.0" | 7.0" | 9 | 10 | 25° – 50° |
| April | 58° | 36° | 4.0" | 3.0" | 12 | 1 | 36° – 53° |
| May | 70° | 48° | 5.1" | 0.3" | 14 | 0 | 53° – 66° |
| June | 80° | 58° | 5.5" | 0.0" | 12 | 0 | 65° – 73° |
| July | 82° | 62° | 4.4" | 0.0" | 10 | 0 | 66° – 78° |
| August | 80° | 59° | 4.0" | 0.0" | 9 | 0 | 64° – 75° |
| September | 74° | 51° | 3.4" | 0.0" | 9 | 0 | 56° – 68° |
| October | 60° | 38° | 2.5" | 0.4" | 9 | 0 | 43° – 54° |
| November | 44° | 26° | 1.7" | 3.0" | 8 | 4 | 26° – 47° |
| December | 30° | 15° | 1.3" | 9.4" | 8 | 16 | 7° – 31° |
| Year | 56° | 36° | 36.0" | 44.4" | 116 | 79 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 25° to 50°. June is the most reliable, staying within 8°.
Where Rockwell’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Rockwell’s center.
- Snow: Mason City Muni Airport.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Mason City, IA, 13 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Rockwell’s climate
What is the weather like in Rockwell?
A typical July afternoon reaches 82°, a January night drops to 8°, and about 44 inches of snow falls in a normal winter. Colder January nights than 95% of U.S. towns; cooler July afternoons than 78% of U.S. towns.
How cold does it get in Rockwell in winter?
January nights average 8°. About 161 nights a year reach 32° or below and 25 reach 0° or below. In the coldest January of the last 30 years the month averaged 5°.
How much snow does Rockwell get?
About 44 inches in a normal winter at Mason City Muni Airport, most of it in January, with snow on the ground about 79 days a year.
How hot does it get in Rockwell?
July, with a typical high of 82° and a low of 62°. About 9 days a year reach 90° (Mason City, IA).
When is the first and last frost in Rockwell?
In half of years the last spring frost (32°) comes by April 29 and the first fall frost by October 7, about 161 frost-free days, at Mason City, IA.
What growing zone is Rockwell in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −18°.
What is the best time of year to visit Rockwell?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Rockwell getting warmer?
Yes: 1991–2020 averaged 1.1° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 71% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Rockwell.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.