Few U.S. towns have colder winter nights than Foster Township
Expect July afternoons of about 86°. The year swings widely: the coldest month’s nights and the warmest month’s afternoons are 79° apart. Precipitation is light here, less than falls on 91% of U.S. towns. Tender plants can go out after about May 11; in half of years the first frost comes by September 30.
A year in Foster Township at a glance
Each month’s typical high and low, and what it brings.
What stands out about Foster Township’s climate
Compared with towns across the U.S., with Foster Township’s place in South Dakota beside it.
What a year in Foster Township 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 11 and the first by September 30. Frost and day counts come from NOAA’s station at Glad Valley 2 W, SD, 15 miles from the town’s center, at about the same height.
The 2023 USDA map puts Foster 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 47 inches of snow a winter
Snow, measured at Glad Valley 2 W, SD, falls mostly in March. Precipitation (rain plus melted snow) adds up to 18 inches a year; June is the wettest month and January the driest. Rain or snow falls on about 82 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Foster Township
94% 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 Glad Valley 2 W, SD.
Living with Foster Township’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 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 30.
Months with highs of 62–84° and lows of 40° or more: May, June and September.
Parks & trails →Cold waves are 41% of the yearly building losses FEMA expects in Foster Township from natural hazards, the largest share. Normals are averages; the hazards page covers the extremes.
Natural hazards →Foster Township and its neighbors
Every town next door is within a degree of Foster Township in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Foster 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 |
|---|---|---|---|---|
| Foster Township, SD | 7° | 86° | 18" | 47" |
| Havre, MT | 6° | 85° | 13" | 41" |
| Gypsum, CO | 11° | 86° | 14" | 39" |
| Watford City, ND | 4° | 84° | 16" | 50" |
| Alliance, NE | 13° | 88° | 17" | 45" |
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 Foster Township averaged 1.3° warmer than the 1900s. The biggest change is in January (+3.8°).
A smaller shift than in 56% 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 Foster Township compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Foster Township’s place among South Dakota’s.
Foster Township weather by month
Highs, lows and precipitation from NOAA’s grid at Foster Township’s center; snow, wet days and snow on the ground from Glad Valley 2 W, SD. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 28° | 7° | 0.4" | 5.3" | 5 | 8° – 32° |
| February | 32° | 11° | 0.6" | 7.6" | 5 | 2° – 33° |
| March | 44° | 21° | 0.9" | 8.8" | 6 | 21° – 46° |
| April | 57° | 31° | 1.8" | 7.5" | 8 | 37° – 50° |
| May | 68° | 42° | 3.1" | 0.7" | 11 | 49° – 60° |
| June | 78° | 52° | 3.3" | 0.0" | 11 | 59° – 69° |
| July | 86° | 58° | 2.6" | 0.0" | 8 | 64° – 79° |
| August | 85° | 56° | 1.8" | 0.0" | 6 | 64° – 76° |
| September | 75° | 46° | 1.3" | 0.3" | 6 | 54° – 67° |
| October | 59° | 32° | 1.5" | 3.8" | 7 | 37° – 51° |
| November | 43° | 20° | 0.5" | 4.8" | 4 | 19° – 42° |
| December | 32° | 10° | 0.5" | 7.7" | 4 | 9° – 30° |
| Year | 57° | 32° | 18.1" | 46.5" | 82 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 2° to 33°. June is the most reliable, staying within 10°.
Where Foster 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 Foster Township’s center.
- Snow: Glad Valley 2 W, SD.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Glad Valley 2 W, SD, 15 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 Foster Township’s climate
What is the weather like in Foster Township?
A typical July afternoon reaches 86°, a January night drops to 7°, and about 47 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 Foster Township in winter?
January nights average 7°. About 181 nights a year reach 32° or below and 30 reach 0° or below. In the coldest January of the last 30 years the month averaged 8°.
How much snow does Foster Township get?
About 47 inches in a normal winter at Glad Valley 2 W, SD, most of it in March.
How hot does it get in Foster Township?
July, with a typical high of 86° and a low of 58°. About 21 days a year reach 90° and 3 reach 100° (Glad Valley 2 W, SD).
When is the first and last frost in Foster Township?
In half of years the last spring frost (32°) comes by May 11 and the first fall frost by September 30, about 140 frost-free days, at Glad Valley 2 W, SD.
What growing zone is Foster 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 Foster 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 Foster Township getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 56% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Foster 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.