Swea City sits near the bottom of U.S. towns for winter warmth
In July the day’s top temperature is typically 82°. By precipitation alone, it ranks drier than 84% of U.S. towns. Since 1901–2000, the year has warmed by 1.0°, most of all in December. Warm coats and heating bills mark the months from October to April, when means dip under 50°.
A year in Swea City at a glance
Each month’s typical high and low, and what it brings.
What stands out about Swea City’s climate
Compared with towns across the U.S., with Swea City’s place in Iowa beside it.
What a year in Swea City feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 150 frost-free days a year
In half of years the last 32° night comes by May 4 and the first by October 1. Frost and day counts come from NOAA’s station at Swea City 5n, IA, 5 miles from the town’s center, at about the same height.
The 2023 USDA map puts Swea City’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 40 inches of snow a winter
Snow, measured at Swea City 5n, IA, falls mostly in January. Precipitation (rain plus melted snow) adds up to 32 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 93 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Swea City
94% 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 Swea City 5n, IA.
Living with Swea City’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
150 frost-free days in zone 5a. The last frost comes by May 4 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 1.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 0.0 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Swea City from natural hazards, drought is the largest share (37%); heat waves, cold waves, winter storms and ice storms together are 18%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Swea City and similar climates
TownRatings has no climate map of the towns around Swea City yet.
Climates most like Swea City’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 |
|---|---|---|---|---|
| Swea City, IA | 7° | 82° | 32" | 40" |
| Menomonie, WI | 5° | 82° | 34" | 41" |
| Isanti, MN | 4° | 82° | 32" | 44" |
| Plattsburgh, NY | 9° | 81° | 35" | 50" |
| Colchester, VT | 10° | 81° | 38" | 50" |
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 Swea City averaged 1.0° warmer than the 1900s. The biggest change is in December (+2.5°).
A smaller shift than in 77% 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 Swea City compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Swea City’s place among Iowa’s.
Swea City weather by month
Highs, lows and precipitation from NOAA’s grid at Swea City’s center; snow, wet days and snow on the ground from Swea City 5n, IA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 24° | 7° | 0.8" | 10.9" | 6 | 23 | 5° – 27° |
| February | 29° | 12° | 0.9" | 8.5" | 5 | 21 | 9° – 31° |
| March | 42° | 24° | 1.7" | 4.6" | 7 | 10 | 26° – 48° |
| April | 57° | 35° | 3.4" | 3.6" | 10 | 1 | 34° – 54° |
| May | 70° | 47° | 4.4" | 0.0" | 12 | 0 | 53° – 64° |
| June | 80° | 58° | 4.9" | 0.0" | 11 | 0 | 65° – 73° |
| July | 82° | 62° | 4.0" | 0.0" | 9 | 0 | 65° – 77° |
| August | 80° | 59° | 3.9" | 0.0" | 8 | 0 | 64° – 74° |
| September | 74° | 51° | 3.2" | 0.0" | 8 | 0 | 56° – 67° |
| October | 60° | 38° | 2.4" | 0.7" | 7 | 0 | 43° – 55° |
| November | 43° | 25° | 1.5" | 3.1" | 6 | 6 | 24° – 46° |
| December | 29° | 13° | 1.2" | 8.3" | 6 | 21 | 7° – 28° |
| Year | 56° | 36° | 32.2" | 39.7" | 93 | 82 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 26° to 48°. June is the most reliable, staying within 8°.
Where Swea City’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 Swea City’s center.
- Snow: Swea City 5n, IA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Swea City 5n, IA, 5 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 Swea City’s climate
What is the weather like in Swea City?
A typical July afternoon reaches 82°, a January night drops to 7°, and about 40 inches of snow falls in a normal winter. Colder January nights than 96% of U.S. towns; cooler July afternoons than 78% of U.S. towns.
How cold does it get in Swea City in winter?
January nights average 7°. About 163 nights a year reach 32° or below and 28 reach 0° or below. In the coldest January of the last 30 years the month averaged 5°.
How much snow does Swea City get?
About 40 inches in a normal winter at Swea City 5n, IA, most of it in January, with snow on the ground about 82 days a year.
How hot does it get in Swea City?
July, with a typical high of 82° and a low of 62°. About 11 days a year reach 90° (Swea City 5n, IA).
When is the first and last frost in Swea City?
In half of years the last spring frost (32°) comes by May 4 and the first fall frost by October 1, about 150 frost-free days, at Swea City 5n, IA.
What growing zone is Swea City 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 Swea City?
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 Swea City getting warmer?
Yes: 1991–2020 averaged 1.0° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 77% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Swea City.
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.