January in Union Township bites harder than in 95% of U.S. towns
Expect July afternoons of about 87°. Seasons differ by 78°, from the coldest nights to the warmest afternoons. It is a dry place: less rain and snow fall here than on 91% of U.S. towns. The heating season runs October to April: each of those months averages under 50°.
A year in Union Township at a glance
Each month’s typical high and low, and what it brings.
What stands out about Union Township’s climate
Compared with towns across the U.S., with Union Township’s place in South Dakota beside it.
What a year in Union Township feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 137 frost-free days a year
In half of years the last 32° night comes by May 11 and the first by September 28. Frost and day counts come from NOAA’s station at Zeona 10 Ssw, SD, 8 miles from the town’s center, at about the same height.
The 2023 USDA map puts Union Township’s center in zone 4b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −24°. 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 43 inches of snow a winter
Snow, measured at Maurine 12sw, SD, falls mostly in April and December. Precipitation (rain plus melted snow) adds up to 17 inches a year; May 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 Union Township
92% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Zeona 10 Ssw, SD.
Living with Union Township’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
137 frost-free days in zone 4b. The last frost comes by May 11 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 28.
Months with highs of 62–84° and lows of 40° or more: May, June and September. 5.1 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Union Township from natural hazards, river flooding is the largest share (50%); heat waves, cold waves, winter storms and ice storms together are 16%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Union Township and similar climates
TownRatings has no climate map of the towns around Union Township yet.
Climates most like Union Township’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 |
|---|---|---|---|---|
| Union Township, SD | 9° | 87° | 17" | 43" |
| Gypsum, CO | 11° | 86° | 14" | 39" |
| Alliance, NE | 13° | 88° | 17" | 45" |
| Sheridan, WY | 11° | 89° | 15" | 33" |
| Havre, MT | 6° | 85° | 13" | 41" |
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 Union Township averaged 1.3° warmer than the 1900s. The biggest change is in January (+3.7°).
A smaller shift than in 51% 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 Union Township compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Union Township’s place among South Dakota’s.
Union Township weather by month
Highs, lows and precipitation from NOAA’s grid at Union Township’s center; snow, wet days and snow on the ground from Maurine 12sw, SD. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 32° | 9° | 0.4" | 5.1" | 4 | 22 | 10° – 34° |
| February | 36° | 12° | 0.5" | 6.9" | 4 | 13 | 5° – 36° |
| March | 46° | 21° | 0.8" | 7.1" | 4 | 10 | 20° – 46° |
| April | 57° | 31° | 1.7" | 8.0" | 8 | 4 | 37° – 50° |
| May | 67° | 41° | 3.4" | 1.2" | 10 | 0 | 48° – 60° |
| June | 78° | 52° | 3.1" | 0.0" | 10 | 0 | 60° – 70° |
| July | 87° | 58° | 2.2" | 0.0" | 8 | 0 | 64° – 78° |
| August | 86° | 55° | 1.6" | 0.0" | 6 | 0 | 64° – 76° |
| September | 76° | 45° | 1.1" | 0.0" | 5 | 0 | 53° – 67° |
| October | 60° | 32° | 1.4" | 2.9" | 6 | 2 | 39° – 51° |
| November | 46° | 20° | 0.5" | 4.3" | 3 | 7 | 22° – 42° |
| December | 34° | 11° | 0.5" | 7.6" | 4 | 16 | 11° – 32° |
| Year | 59° | 32° | 17.1" | 43.1" | 71 | 75 |
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 36°. June is the most reliable, staying within 11°.
Where Union Township’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 Union Township’s center.
- Snow: Maurine 12sw, SD.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Zeona 10 Ssw, SD, 8 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 Union Township’s climate
What is the weather like in Union Township?
A typical July afternoon reaches 87°, a January night drops to 9°, and about 43 inches of snow falls in a normal winter. Colder January nights than 95% of U.S. towns; hotter July afternoons than 62% of U.S. towns.
How cold does it get in Union Township in winter?
January nights average 9°. About 187 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 10°.
How much snow does Union Township get?
About 43 inches in a normal winter at Maurine 12sw, SD, most of it in April and December, with snow on the ground about 75 days a year.
How hot does it get in Union Township?
July, with a typical high of 87° and a low of 58°. About 31 days a year reach 90° and 4 reach 100° (Zeona 10 Ssw, SD).
When is the first and last frost in Union Township?
In half of years the last spring frost (32°) comes by May 11 and the first fall frost by September 28, about 137 frost-free days, at Zeona 10 Ssw, SD.
What growing zone is Union Township in?
Zone 4b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −24°.
What is the best time of year to visit Union Township?
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 Union Township getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 51% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Union Township.
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.