Few U.S. towns have colder winter nights than O'Neil Township
The warmest part of a July day comes in at 84° on average. Precipitation is light here, less than falls on 89% of U.S. towns. Since 1901–2000, the year has warmed by 0.9°, most of all in January. Homes need heating from October to April, the months averaging under 50°.
A year in O'Neil Township at a glance
Each month’s typical high and low, and what it brings.
What stands out about O'Neil Township’s climate
Compared with towns across the U.S., with O'Neil Township’s place in South Dakota beside it.
What a year in O'Neil Township feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 139 frost-free days a year
In half of years the last 32° night comes by May 10 and the first by September 28. Frost and day counts come from NOAA’s station at Faulkton 1 Nw, SD, 13 miles from the town’s center, 210 ft lower.
The 2023 USDA map puts O'Neil Township’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 43 inches of snow a winter
Snow, measured at Seneca, 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 74 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in O'Neil Township
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 Faulkton 1 Nw, SD.
Living with O'Neil Township’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
139 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 28.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 6.8 miles of trails are waiting.
Parks & trails →Cold waves are 42% of the yearly building losses FEMA expects in O'Neil Township from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →O'Neil Township and its neighbors
Every town next door is within a degree of O'Neil Township in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like O'Neil 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 |
|---|---|---|---|---|
| O'Neil Township, SD | 5° | 84° | 21" | 43" |
| Dickinson, ND | 5° | 83° | 16" | 35" |
| Montevideo, MN | 4° | 83° | 28" | 46" |
| Sidney, MT | 4° | 85° | 15" | 30" |
| Sheldon, IA | 7° | 84° | 30" | 41" |
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 O'Neil Township 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 O'Neil Township compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with O'Neil Township’s place among South Dakota’s.
O'Neil Township weather by month
Highs, lows and precipitation from NOAA’s grid at O'Neil Township’s center; snow, wet days and snow on the ground from Seneca, SD. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 23° | 5° | 0.5" | 6.6" | 4 | 3° – 29° |
| February | 28° | 9° | 0.6" | 10.9" | 6 | 1° – 30° |
| March | 41° | 20° | 0.9" | 6.2" | 5 | 20° – 45° |
| April | 56° | 31° | 1.9" | 5.9" | 8 | 34° – 49° |
| May | 68° | 43° | 3.2" | 0.0" | 9 | 50° – 62° |
| June | 78° | 54° | 3.5" | 0.0" | 10 | 60° – 70° |
| July | 84° | 59° | 2.9" | 0.0" | 6 | 63° – 78° |
| August | 82° | 56° | 2.4" | 0.0" | 6 | 64° – 73° |
| September | 73° | 47° | 2.0" | 0.0" | 6 | 54° – 65° |
| October | 58° | 34° | 1.8" | 1.2" | 6 | 38° – 51° |
| November | 41° | 21° | 0.6" | 2.8" | 4 | 18° – 41° |
| December | 28° | 10° | 0.5" | 9.3" | 4 | 5° – 27° |
| Year | 55° | 32° | 20.8" | 42.9" | 74 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 1° to 30°. August is the most reliable, staying within 9°.
Where O'Neil 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 O'Neil Township’s center.
- Snow: Seneca, SD.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Faulkton 1 Nw, SD, 13 miles from the town’s center, 210 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 O'Neil Township’s climate
What is the weather like in O'Neil Township?
A typical July afternoon reaches 84°, a January night drops to 5°, and about 43 inches of snow falls in a normal winter. Colder January nights than all but 181 U.S. towns; cooler July afternoons than 63% of U.S. towns.
How cold does it get in O'Neil Township in winter?
January nights average 5°. About 172 nights a year reach 32° or below and 31 reach 0° or below. In the coldest January of the last 30 years the month averaged 3°.
How much snow does O'Neil Township get?
About 43 inches in a normal winter at Seneca, SD, most of it in February.
How hot does it get in O'Neil Township?
July, with a typical high of 84° and a low of 59°. About 22 days a year reach 90° and 2 reach 100° (Faulkton 1 Nw, SD).
When is the first and last frost in O'Neil Township?
In half of years the last spring frost (32°) comes by May 10 and the first fall frost by September 28, about 139 frost-free days, at Faulkton 1 Nw, SD.
What growing zone is O'Neil Township 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 O'Neil Township?
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 O'Neil Township 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 O'Neil 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.