Duncan, SC climate
Duncan has mild winters and warm summers, with plenty of rain. A typical July afternoon reaches 90°, a January night drops to 32°, and about 4 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Duncan feels like
Winter
Spring
Summer
Fall
Duncan 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 | 52° | 32° | 4.3" | 1.6" | 10 | 1 | 36° – 48° |
| February | 57° | 35° | 3.8" | 1.0" | 9 | 1 | 38° – 54° |
| March | 64° | 41° | 4.6" | 0.6" | 10 | 0 | 46° – 62° |
| April | 73° | 48° | 4.2" | 0 | 10 | 0 | 56° – 65° |
| May | 80° | 57° | 4.0" | 0 | 10 | 0 | 64° – 74° |
| June | 86° | 65° | 4.3" | 0 | 11 | 0 | 72° – 80° |
| July | 90° | 69° | 4.3" | 0 | 12 | 0 | 76° – 83° |
| August | 88° | 68° | 4.6" | 0 | 11 | 0 | 75° – 84° |
| September | 82° | 62° | 4.0" | 0 | 8 | 0 | 68° – 78° |
| October | 73° | 51° | 3.7" | 0 | 7 | 0 | 58° – 66° |
| November | 63° | 40° | 3.9" | 0.1" | 9 | 0 | 46° – 56° |
| December | 54° | 35° | 4.6" | 0.6" | 10 | 0 | 36° – 54° |
| Year | 72° | 50° | 50.3" | 3.9" | 117 | 2 |
“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 Duncan
Duncan gets 50 inches of rain and melted snow a year. March is the wettest month and October the driest. Rain or snow falls on about 117 days a year.
About 224 frost-free days a year
In half of years the last 32° night comes by March 28 and the first one by November 7. That leaves about 224 frost-free days for gardens, longer than 84% of U.S. towns.
Heating and cooling a home in Duncan
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Duncan, 64% of that work is heating and 36% is cooling.
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.
Duncan and its neighbors
Duncan borders 4 towns with climate data. January nights across them vary by 0.5°. Startex has both the coldest January nights (32°) and the hottest July afternoons (90°). Duncan’s January low is 32° and its July high 90°.
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.
How Duncan 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 Duncan averaged 1.1° warmer than the 1900s. The biggest change is in December (+2.1°). The shift is smaller than in 57% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Duncan’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. December swings the most: between 1991 and 2020 its average temperature ranged from 36° to 54°. July is the most reliable, staying within 7°.
Common questions about Duncan’s climate
What is the coldest month in Duncan?
January, with a typical high of 52° and a low of 32°.
What is the hottest month in Duncan?
July, with a typical high of 90° and a low of 69°. About 48 days a year reach 90°.
How much snow does Duncan get?
About 4 inches in a normal winter, most of it in January.
When is the first frost in Duncan?
In half of years the first 32° night comes by November 7, and the last spring frost by March 28.
What is the rainiest month in Duncan?
March, with 4.6 inches of rain and melted snow. The year totals 50 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Duncan itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Greer, SC (5 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.