Hardly any U.S. towns see harsher January nights than Erwin
Sunny July days climb to about 82°. Its yearly precipitation falls short of 87% of U.S. towns. The latest 30-year average runs 1.2° warmer than 1901–2000’s, with January up the most. From May to September, highs of 67–82° make it easy to spend the day outdoors.
A year in Erwin at a glance
Each month’s typical high and low, and what it brings.
What stands out about Erwin’s climate
Compared with towns across the U.S., with Erwin’s place in South Dakota beside it.
What a year in Erwin feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 151 frost-free days a year
In half of years the last 32° night comes by May 5 and the first by October 4. Frost and day counts come from NOAA’s station at De Smet, SD, 9 miles from the town’s center, 150 ft lower.
The 2023 USDA map puts Erwin’s center in zone 4b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −23°. 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 48 inches of snow a winter
Snow, measured at Bryant, SD, falls mostly in December. Precipitation (rain plus melted snow) adds up to 26 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 73 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Erwin
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 De Smet, SD.
Living with Erwin’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
151 frost-free days in zone 4b. The last frost comes by May 5 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 4.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 0.3 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Erwin from natural hazards, river flooding is the largest share (33%); heat waves, cold waves, winter storms and ice storms together are 33%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Erwin and similar climates
TownRatings has no climate map of the towns around Erwin yet.
Climates most like Erwin’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 |
|---|---|---|---|---|
| Erwin, SD | 4° | 82° | 26" | 48" |
| Hutchinson, MN | 5° | 82° | 29" | 50" |
| Fargo, ND | 0° | 82° | 24" | 51" |
| Kingsford, MI | 5° | 80° | 29" | 61" |
| Hudson, WI | 6° | 82° | 33" | 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 Erwin averaged 1.2° warmer than the 1900s. The biggest change is in January (+3.3°).
A smaller shift than in 61% 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 Erwin compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Erwin’s place among South Dakota’s.
Erwin weather by month
Highs, lows and precipitation from NOAA’s grid at Erwin’s center; snow, wet days and snow on the ground from Bryant, SD. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 23° | 4° | 0.6" | 8.1" | 4 | 22 | 2° – 27° |
| February | 28° | 8° | 0.7" | 8.0" | 4 | 17 | 4° – 30° |
| March | 40° | 21° | 1.2" | 6.4" | 5 | 11 | 20° – 46° |
| April | 55° | 32° | 2.5" | 6.9" | 7 | 3 | 34° – 50° |
| May | 67° | 45° | 3.3" | 0.0" | 9 | 0 | 51° – 63° |
| June | 77° | 56° | 4.1" | 0.0" | 9 | 0 | 61° – 70° |
| July | 82° | 60° | 3.4" | 0.0" | 8 | 0 | 62° – 78° |
| August | 80° | 58° | 3.2" | 0.0" | 6 | 0 | 64° – 73° |
| September | 72° | 49° | 2.7" | 0.0" | 7 | 0 | 53° – 67° |
| October | 57° | 35° | 2.2" | 1.3" | 6 | 1 | 38° – 51° |
| November | 41° | 22° | 1.0" | 7.3" | 4 | 7 | 20° – 41° |
| December | 27° | 10° | 0.7" | 9.7" | 4 | 18 | 5° – 25° |
| Year | 54° | 33° | 25.6" | 47.7" | 73 | 78 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 20° to 46°. August is the most reliable, staying within 9°.
Where Erwin’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 Erwin’s center.
- Snow: Bryant, SD.
- Frost, freezing nights, 90° and 100° days, heating and cooling: De Smet, SD, 9 miles from the town’s center, 150 ft lower; 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 Erwin’s climate
What is the weather like in Erwin?
A typical July afternoon reaches 82°, a January night drops to 4°, and about 48 inches of snow falls in a normal winter. Colder January nights than all but 169 U.S. towns; cooler July afternoons than 79% of U.S. towns.
How cold does it get in Erwin in winter?
January nights average 4°. About 165 nights a year reach 32° or below and 27 reach 0° or below. In the coldest January of the last 30 years the month averaged 2°.
How much snow does Erwin get?
About 48 inches in a normal winter at Bryant, SD, most of it in December, with snow on the ground about 78 days a year.
How hot does it get in Erwin?
July, with a typical high of 82° and a low of 60°. About 10 days a year reach 90° (De Smet, SD).
When is the first and last frost in Erwin?
In half of years the last spring frost (32°) comes by May 5 and the first fall frost by October 4, about 151 frost-free days, at De Smet, SD.
What growing zone is Erwin in?
Zone 4b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −23°.
What is the best time of year to visit Erwin?
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 Erwin getting warmer?
Yes: 1991–2020 averaged 1.2° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 61% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Erwin.
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.