Union Downtown Historic District (Boundary Increase) · Photo: Bill Fitzpatrick · CC BY-SA 3.0Summer arrives in force in Union, hotter than in 82% of U.S. towns
Nights in January average 31°. Seasons differ by 60°, from the coldest nights to the warmest afternoons. Winters are mild: January nights here are milder than in 74% of U.S. towns. Tender plants can go out after about April 4; in half of years the first frost comes by November 1.
A year in Union at a glance
Each month’s typical high and low, and what it brings.
What stands out about Union’s climate
Compared with towns across the U.S., with Union’s place in South Carolina beside it.
What a year in Union feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 210 frost-free days a year
In half of years the last 32° night comes by April 4 and the first by November 1. Day counts come from NOAA’s station at Union 8 S, SC, 8 miles from the town’s center, at about the same height; frost dates and degree days from Santuck, SC, 9 miles away.
The 2023 USDA map puts Union’s center in zone 8a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 12°. 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 46 inches of rain a year
March is the wettest month and October the driest. Rain falls on about 103 days a year. Snow is rare: about 0.1" in a normal year at Lockhart, SC, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Union
63% of the work is heating. Months averaging under 55° run from November through March.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Santuck, SC.
Living with Union’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
210 frost-free days in zone 8a. The last frost comes by Apr 4 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 1.
Months with highs of 62–84° and lows of 40° or more: March, April, May, September and October. 0.6 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Union from natural hazards, river flooding is the largest share (34%); heat waves, cold waves, winter storms and ice storms together are 17%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Union and similar climates
TownRatings has no climate map of the towns around Union yet.
Climates most like Union’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 |
|---|---|---|---|---|
| Union, SC | 31° | 91° | 46" | 0.1" |
| Spout Springs, NC | 32° | 90° | 47" | 1.1" |
| Cartersville, GA | 32° | 90° | 49" | 0.0" |
| Walnut Ridge, AR | 28° | 90° | 49" | 0.9" |
| Emporia, VA | 29° | 90° | 48" | 1.4" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Union averaged 0.9° warmer than the 1900s. The biggest change is in February (+1.8°).
A smaller shift than in 86% 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 Union compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Union’s place among South Carolina’s.
Union weather by month
Highs, lows and precipitation from NOAA’s grid at Union’s center; snow, wet days and snow on the ground from Lockhart, SC. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 53° | 31° | 3.9" | 0.0" | 9 | 0 | 36° – 48° |
| February | 58° | 34° | 3.5" | 0.0" | 9 | 0 | 39° – 54° |
| March | 65° | 40° | 4.2" | 0.0" | 9 | 0 | 47° – 62° |
| April | 74° | 48° | 3.7" | 0.0" | 8 | 0 | 57° – 65° |
| May | 81° | 57° | 3.5" | 0.0" | 8 | 0 | 64° – 73° |
| June | 88° | 65° | 4.2" | 0.0" | 10 | 0 | 72° – 81° |
| July | 91° | 69° | 3.5" | 0.0" | 9 | 0 | 77° – 84° |
| August | 89° | 68° | 4.1" | 0.0" | 9 | 0 | 76° – 84° |
| September | 83° | 62° | 3.6" | 0.0" | 7 | 0 | 69° – 78° |
| October | 74° | 50° | 3.3" | 0.0" | 7 | 0 | 58° – 66° |
| November | 63° | 39° | 3.6" | 0.0" | 8 | 0 | 47° – 56° |
| December | 56° | 34° | 4.2" | 0.1" | 10 | 0 | 35° – 55° |
| Year | 73° | 50° | 45.5" | 0.1" | 103 | 0 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 35° to 55°. July is the most reliable, staying within 7°.
Where Union’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 Union’s center.
- Snow: Lockhart, SC.
- Frost dates, heating and cooling: Santuck, SC, 9 miles away.
- Freezing nights, 90° and 100° days: Union 8 S, SC, 8 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 Union’s climate
What is the weather like in Union?
A typical July afternoon reaches 91°, a January night drops to 31°, and snow is almost unheard of. Milder January nights than 74% of U.S. towns; hotter July afternoons than 82% of U.S. towns.
How cold does it get in Union in winter?
January nights average 31°. About 87 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 36°.
How much snow does Union get?
About 0.1 inches in a normal winter at Lockhart, SC, so most winters see none.
How hot does it get in Union?
July, with a typical high of 91° and a low of 69°. About 56 days a year reach 90° and 3 reach 100° (Santuck, SC).
When is the first and last frost in Union?
In half of years the last spring frost (32°) comes by April 4 and the first fall frost by November 1, about 210 frost-free days, at Santuck, SC.
What growing zone is Union in?
Zone 8a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 12°.
What is the best time of year to visit Union?
By one simple rule (highs of 62–84° and lows of 40° or more), March, April, May, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Union getting warmer?
Yes: 1991–2020 averaged 0.9° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 86% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Union.
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.