Hardly any U.S. towns see harsher January nights than Stephan
Expect July afternoons of about 86°. The wettest month is June; the driest is January. By precipitation alone, it ranks drier than 89% of U.S. towns. Tender plants can go out after about May 10; in half of years the first frost comes by September 29.
A year in Stephan at a glance
Each month’s typical high and low, and what it brings.
What stands out about Stephan’s climate
Compared with towns across the U.S., with Stephan’s place in South Dakota beside it.
What a year in Stephan feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 140 frost-free days a year
In half of years the last 32° night comes by May 10 and the first by September 29. Frost and day counts come from NOAA’s station at Stephan 2 Nw, SD, 1.4 miles from the town’s center, at about the same height.
The 2023 USDA map puts Stephan’s center in zone 4b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −22°. 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 37 inches of snow a winter
Snow, measured at Stephan 2 Nw, SD, falls mostly in February. Precipitation (rain plus melted snow) adds up to 21 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 71 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Stephan
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 Stephan 2 Nw, SD.
Living with Stephan’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
140 frost-free days in zone 4b. The last frost comes by May 10 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 29.
Months with highs of 62–84° and lows of 40° or more: May, June and September.
Parks & trails →Of the yearly building losses FEMA expects in Stephan from natural hazards, river flooding is the largest share (42%); heat waves, cold waves, winter storms and ice storms together are 27%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Stephan and similar climates
TownRatings has no climate map of the towns around Stephan yet.
Climates most like Stephan’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 |
|---|---|---|---|---|
| Stephan, SD | 8° | 86° | 21" | 37" |
| Sidney, MT | 4° | 85° | 15" | 30" |
| Norfolk, NE | 12° | 86° | 28" | 30" |
| Gypsum, CO | 11° | 86° | 14" | 39" |
| Sioux City, IA | 10° | 86° | 29" | 36" |
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 Stephan averaged 0.9° warmer than the 1900s. The biggest change is in January (+3.3°).
A smaller shift than in 86% 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 Stephan compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Stephan’s place among South Dakota’s.
Stephan weather by month
Highs, lows and precipitation from NOAA’s grid at Stephan’s center; snow, wet days and snow on the ground from Stephan 2 Nw, SD. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 27° | 8° | 0.5" | 6.0" | 4 | 8° – 33° |
| February | 32° | 11° | 0.7" | 9.3" | 4 | 5° – 33° |
| March | 45° | 22° | 0.9" | 6.5" | 4 | 23° – 47° |
| April | 58° | 32° | 2.2" | 4.4" | 7 | 35° – 51° |
| May | 69° | 44° | 3.3" | 0.0" | 9 | 51° – 63° |
| June | 79° | 55° | 3.7" | 0.0" | 10 | 62° – 71° |
| July | 86° | 60° | 2.9" | 0.0" | 7 | 65° – 80° |
| August | 84° | 58° | 2.3" | 0.0" | 6 | 66° – 75° |
| September | 76° | 49° | 2.0" | 0.0" | 6 | 57° – 68° |
| October | 60° | 35° | 1.7" | 1.1" | 6 | 40° – 53° |
| November | 44° | 22° | 0.6" | 5.0" | 3 | 22° – 42° |
| December | 31° | 12° | 0.5" | 4.3" | 4 | 9° – 29° |
| Year | 58° | 34° | 21.4" | 36.6" | 71 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 5° to 33°. August is the most reliable, staying within 9°.
Where Stephan’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 Stephan’s center.
- Snow: Stephan 2 Nw, SD (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Stephan 2 Nw, SD, 1.4 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 Stephan’s climate
What is the weather like in Stephan?
A typical July afternoon reaches 86°, a January night drops to 8°, and about 37 inches of snow falls in a normal winter. Colder January nights than 96% of U.S. towns; hotter July afternoons than 57% of U.S. towns.
How cold does it get in Stephan in winter?
January nights average 8°. About 179 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 8°.
How much snow does Stephan get?
About 37 inches in a normal winter at Stephan 2 Nw, SD, most of it in February.
How hot does it get in Stephan?
July, with a typical high of 86° and a low of 60°. About 26 days a year reach 90° and 3 reach 100° (Stephan 2 Nw, SD).
When is the first and last frost in Stephan?
In half of years the last spring frost (32°) comes by May 10 and the first fall frost by September 29, about 140 frost-free days, at Stephan 2 Nw, SD.
What growing zone is Stephan in?
Zone 4b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −22°.
What is the best time of year to visit Stephan?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Stephan getting warmer?
Yes: 1991–2020 averaged 0.9° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 86% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Stephan.
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.