Merton, SD climate
Merton has cold winters and pleasant summers. A typical July afternoon reaches 82°, a January night drops to 4°.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Merton feels like
Winter
Spring
Summer
Fall
Merton weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | 30-yr range |
|---|---|---|---|---|
| January | 22° | 4° | 0.6" | 1° – 26° |
| February | 27° | 8° | 0.7" | 4° – 29° |
| March | 40° | 20° | 1.1" | 19° – 44° |
| April | 55° | 32° | 2.2" | 34° – 51° |
| May | 67° | 44° | 3.2" | 51° – 63° |
| June | 77° | 55° | 4.1" | 61° – 70° |
| July | 82° | 60° | 3.5" | 62° – 78° |
| August | 80° | 58° | 2.9" | 63° – 73° |
| September | 72° | 48° | 2.6" | 53° – 66° |
| October | 57° | 35° | 2.2" | 38° – 51° |
| November | 40° | 21° | 0.8" | 20° – 42° |
| December | 27° | 10° | 0.7" | 5° – 25° |
| Year | 54° | 33° | 24.6" |
“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 Merton
Merton gets 25 inches of rain and melted snow a year. June is the wettest month and January the driest.
About 153 frost-free days a year
In half of years the last 32° night comes by May 5 and the first one by October 5. That leaves about 153 frost-free days for gardens, shorter than 78% of U.S. towns.
Heating and cooling a home in Merton
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Merton, 94% of that work is heating and 6% 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.
Merton and its neighbors
Merton borders 4 towns with climate data. January nights across them vary by 1.2°. Day has the coldest January nights (3°) and Darlington the hottest July afternoons (83°). Merton’s January low is 4° and its July high 82°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Merton 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 Merton averaged 1.2° warmer than the 1900s. The biggest change is in January (+3.1°). The shift is smaller than in 53% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Merton’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 4° to 29°. June is the most reliable, staying within 10°.
Common questions about Merton’s climate
What is the coldest month in Merton?
January, with a typical high of 22° and a low of 4°.
What is the hottest month in Merton?
July, with a typical high of 82° and a low of 60°. About 9 days a year reach 90°.
When is the first frost in Merton?
In half of years the first 32° night comes by October 5, and the last spring frost by May 5.
What is the rainiest month in Merton?
June, with 4.1 inches of rain and melted snow. The year totals 25 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Merton itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Clark, SD (9 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.