Foster, SD climate
Foster has cold, snowy winters and warm summers. A typical July afternoon reaches 86°, a January night drops to 8°, and about 36 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Foster feels like
Winter
Spring
Summer
Fall
Foster weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 28° | 8° | 0.5" | 6.1" | 5 | 19 | 8° – 33° |
| February | 34° | 13° | 0.8" | 8.0" | 5 | 11 | 9° – 34° |
| March | 46° | 24° | 1.3" | 5.2" | 6 | 7 | 25° – 51° |
| April | 59° | 34° | 2.9" | 4.7" | 8 | 2 | 37° – 53° |
| May | 71° | 47° | 3.7" | 0 | 11 | 0 | 53° – 65° |
| June | 81° | 58° | 3.9" | 0 | 10 | 0 | 65° – 74° |
| July | 86° | 62° | 3.0" | 0 | 8 | 0 | 66° – 82° |
| August | 83° | 60° | 3.1" | 0 | 7 | 0 | 66° – 76° |
| September | 76° | 50° | 2.8" | 0 | 7 | 0 | 57° – 69° |
| October | 62° | 37° | 2.1" | 0.9" | 7 | 1 | 42° – 54° |
| November | 46° | 23° | 1.0" | 3.2" | 4 | 3 | 25° – 44° |
| December | 32° | 13° | 0.8" | 8.2" | 5 | 15 | 10° – 28° |
| Year | 59° | 36° | 25.7" | 36.3" | 81 | 58 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Foster
Foster gets 26 inches of rain and melted snow a year. June is the wettest month and January the driest. Rain or snow falls on about 81 days a year. Snow covers the ground about 58 days of the year.
About 161 frost-free days a year
In half of years the last 32° night comes by April 30 and the first one by October 7. That leaves about 161 frost-free days for gardens, shorter than 70% of U.S. towns.
Heating and cooling a home in Foster
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Foster, 91% of that work is heating and 9% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
Foster and its neighbors
Foster borders 4 towns with climate data. January nights across them vary by 0.4°. Milltown has the coldest January nights (8°) and Cross Plains the hottest July afternoons (87°). Foster’s January low is 8° and its July high 86°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Foster compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Foster averaged 0.8° warmer than the 1900s. The biggest change is in January (+2.8°). The shift is smaller than in 82% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Foster’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. March swings the most: between 1991 and 2020 its average temperature ranged from 25° to 51°. June is the most reliable, staying within 9°.
Common questions about Foster’s climate
What is the coldest month in Foster?
January, with a typical high of 28° and a low of 8°.
What is the hottest month in Foster?
July, with a typical high of 86° and a low of 62°. About 19 days a year reach 90°.
How much snow does Foster get?
About 36 inches in a normal winter, most of it in December.
When is the first frost in Foster?
In half of years the first 32° night comes by October 7, and the last spring frost by April 30.
What is the rainiest month in Foster?
June, with 3.9 inches of rain and melted snow. The year totals 26 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Foster itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Alexandria, SD (12 mi, snow) and Bridgewater, SD (16 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.