Few U.S. towns have colder winter nights than Lyon Township
Expect July afternoons of about 87°. By precipitation alone, it ranks drier than 88% of U.S. towns. Since 1901–2000, the year has warmed by 1.3°, most of all in January. The heating season runs October to April: each of those months averages under 50°.
A year in Lyon Township at a glance
Each month’s typical high and low, and what it brings.
What stands out about Lyon Township’s climate
Compared with towns across the U.S., with Lyon Township’s place in South Dakota beside it.
What a year in Lyon Township feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 148 frost-free days a year
In half of years the last 32° night comes by May 6 and the first by October 1. Frost and day counts come from NOAA’s station at Gann Valley 4nw, SD, 11 miles from the town’s center, at about the same height.
The 2023 USDA map puts Lyon Township’s center in zone 4b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −20°. 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 Chamberlain 5 S, SD, falls mostly in January, February, March and December. Precipitation (rain plus melted snow) adds up to 23 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 93 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Lyon Township
91% 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 Gann Valley 4nw, SD.
Living with Lyon Township’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
148 frost-free days in zone 4b. The last frost comes by May 6 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 1.
Months with highs of 62–84° and lows of 40° or more: May, June and September. 2.0 miles of trails are waiting.
Parks & trails →Cold waves are 60% of the yearly building losses FEMA expects in Lyon Township from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →Lyon Township and its neighbors
Every town next door is within a degree of Lyon Township in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Lyon 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 |
|---|---|---|---|---|
| Lyon Township, SD | 8° | 87° | 23" | 43" |
| Sioux City, IA | 10° | 86° | 29" | 36" |
| Alliance, NE | 13° | 88° | 17" | 45" |
| Gypsum, CO | 11° | 86° | 14" | 39" |
| Marshall, MN | 6° | 84° | 28" | 44" |
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 Lyon Township averaged 1.3° warmer than the 1900s. The biggest change is in January (+3.8°).
A smaller shift than in 54% 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 Lyon Township compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Lyon Township’s place among South Dakota’s.
Lyon Township weather by month
Highs, lows and precipitation from NOAA’s grid at Lyon Township’s center; snow, wet days and snow on the ground from Chamberlain 5 S, SD. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 29° | 8° | 0.5" | 7.3" | 6 | 18 | 9° – 34° |
| February | 34° | 12° | 0.7" | 8.0" | 6 | 12 | 8° – 34° |
| March | 46° | 23° | 1.0" | 7.2" | 6 | 10 | 23° – 49° |
| April | 58° | 33° | 2.5" | 6.8" | 10 | 2 | 36° – 52° |
| May | 70° | 45° | 3.4" | 0.0" | 11 | 0 | 52° – 64° |
| June | 80° | 56° | 3.8" | 0.0" | 11 | 0 | 64° – 72° |
| July | 87° | 61° | 2.8" | 0.0" | 9 | 0 | 65° – 81° |
| August | 85° | 59° | 2.8" | 0.0" | 8 | 0 | 66° – 76° |
| September | 77° | 49° | 2.3" | 0.0" | 7 | 0 | 56° – 68° |
| October | 61° | 36° | 1.8" | 1.4" | 7 | 1 | 41° – 54° |
| November | 45° | 23° | 0.7" | 5.1" | 5 | 5 | 24° – 43° |
| December | 32° | 13° | 0.6" | 7.5" | 6 | 15 | 10° – 29° |
| Year | 59° | 35° | 22.8" | 43.3" | 93 | 64 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 8° to 34°. June is the most reliable, staying within 9°.
Where Lyon 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 Lyon Township’s center.
- Snow: Chamberlain 5 S, SD.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Gann Valley 4nw, SD, 11 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 Lyon Township’s climate
What is the weather like in Lyon Township?
A typical July afternoon reaches 87°, a January night drops to 8°, and about 43 inches of snow falls in a normal winter. Colder January nights than 96% of U.S. towns; hotter July afternoons than 61% of U.S. towns.
How cold does it get in Lyon Township in winter?
January nights average 8°. About 179 nights a year reach 32° or below and 29 reach 0° or below. In the coldest January of the last 30 years the month averaged 9°.
How much snow does Lyon Township get?
About 43 inches in a normal winter at Chamberlain 5 S, SD, most of it in January, February, March and December, with snow on the ground about 64 days a year.
How hot does it get in Lyon Township?
July, with a typical high of 87° and a low of 61°. About 27 days a year reach 90° and 4 reach 100° (Gann Valley 4nw, SD).
When is the first and last frost in Lyon Township?
In half of years the last spring frost (32°) comes by May 6 and the first fall frost by October 1, about 148 frost-free days, at Gann Valley 4nw, SD.
What growing zone is Lyon Township in?
Zone 4b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −20°.
What is the best time of year to visit Lyon 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 Lyon Township getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 54% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Lyon 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.