Photo: Jared Winkler · CC BY-SA 4.0Sergeant Bluff’s winters are colder and snowier than most of the U.S.
A typical July afternoon reaches 86°, a January night drops to 11°, and about 36 inches of snow falls in a normal winter.
A year in Sergeant Bluff at a glance
Each month’s typical high and low, and what it brings.
What stands out about Sergeant Bluff’s climate
Compared with towns across the U.S., with Sergeant Bluff’s place in Iowa beside it.
What a year in Sergeant Bluff feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 159 frost-free days a year
In half of years the last 32° night comes by April 29 and the first by October 5. Frost and day counts come from NOAA’s station at Sioux City Gateway Airport, 1.5 miles from the town’s center, at about the same height.
The 2023 USDA map puts Sergeant Bluff’s center in zone 5a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −16°. 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 36 inches of snow a winter
Snow, measured at Sioux City Gateway Airport, falls mostly in February. Precipitation (rain plus melted snow) adds up to 30 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 102 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Sergeant Bluff
89% 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 Sioux City Gateway Airport.
Living with Sergeant Bluff’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
159 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 5.
Months with highs of 62–84° and lows of 40° or more: May, June, August and September. 0.7 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Sergeant Bluff from natural hazards, tornadoes are the largest share (39%); heat waves, cold waves, winter storms and ice storms together are 20%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Sergeant Bluff and its neighbors
Every town next door is within a degree of Sergeant Bluff in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Sergeant Bluff’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 |
|---|---|---|---|---|
| Sergeant Bluff, IA | 11° | 86° | 30" | 36" |
| Hastings, NE | 15° | 87° | 27" | 29" |
| Huron, SD | 6° | 86° | 23" | 44" |
| Redwood Falls, MN | 6° | 83° | 29" | 44" |
| Rock Island, IL | 14° | 85° | 37" | 36" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Sergeant Bluff averaged 1.1° warmer than the 1900s. The biggest change is in January (+2.5°).
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 Sergeant Bluff compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Sergeant Bluff’s place among Iowa’s.
Sergeant Bluff weather by month
Highs, lows and precipitation from NOAA’s grid at Sergeant Bluff’s center; snow, wet days and snow on the ground from Sioux City Gateway Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 30° | 11° | 0.6" | 7.7" | 7 | 20 | 12° – 33° |
| February | 35° | 15° | 0.8" | 8.7" | 7 | 15 | 14° – 35° |
| March | 48° | 26° | 1.6" | 5.7" | 8 | 7 | 29° – 53° |
| April | 62° | 37° | 3.1" | 2.3" | 10 | 1 | 41° – 55° |
| May | 73° | 49° | 4.0" | 0.0" | 12 | 0 | 55° – 67° |
| June | 82° | 60° | 4.6" | 0.0" | 12 | 0 | 67° – 76° |
| July | 86° | 64° | 3.4" | 0.0" | 9 | 0 | 68° – 81° |
| August | 83° | 61° | 3.9" | 0.0" | 10 | 0 | 66° – 77° |
| September | 77° | 52° | 2.9" | 0.0" | 8 | 0 | 58° – 70° |
| October | 63° | 39° | 2.3" | 0.8" | 8 | 0 | 44° – 55° |
| November | 47° | 26° | 1.3" | 3.2" | 6 | 3 | 27° – 47° |
| December | 33° | 15° | 1.0" | 7.6" | 7 | 13 | 11° – 31° |
| Year | 60° | 38° | 29.5" | 36.0" | 102 | 58 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 29° to 53°. June is the most reliable, staying within 9°.
Where Sergeant Bluff’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 Sergeant Bluff’s center.
- Snow: Sioux City Gateway Airport (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Sioux City Gateway Airport, 1.5 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 Sergeant Bluff’s climate
What is the weather like in Sergeant Bluff?
A typical July afternoon reaches 86°, a January night drops to 11°, and about 36 inches of snow falls in a normal winter. Colder January nights than 93% of U.S. towns; hotter July afternoons than 54% of U.S. towns.
How cold does it get in Sergeant Bluff in winter?
January nights average 11°. About 154 nights a year reach 32° or below and 16 reach 0° or below. In the coldest January of the last 30 years the month averaged 12°.
How much snow does Sergeant Bluff get?
About 36 inches in a normal winter at Sioux City Gateway Airport, most of it in February, with snow on the ground about 58 days a year.
How hot does it get in Sergeant Bluff?
July, with a typical high of 86° and a low of 64°. About 25 days a year reach 90° (Sioux City Gateway Airport).
When is the first and last frost in Sergeant Bluff?
In half of years the last spring frost (32°) comes by April 29 and the first fall frost by October 5, about 159 frost-free days, at Sioux City Gateway Airport.
What growing zone is Sergeant Bluff in?
Zone 5a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −16°.
What is the best time of year to visit Sergeant Bluff?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Sergeant Bluff 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 Sergeant Bluff.
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.