Climate and monthly weather forecastSumter, SC
Climate and monthly weather forecast
The climate of Sumter
Sumter, South Carolina, USA lies under Köppen's climate classification of Cfa. This classification implies that Sumter has a humid subtropical climate lacking a dry season. The year-round conditions depict considerable variations in the weather parameters.The average high and low temperature in Sumter changes noticeably as the year progresses. Starting with highs of 52.9°F (11.6°C) and lows of 38.1°F (3.4°C) in January, it escalates reaching peaks in July with highs of 90.7°F (32.6°C) and lows of 72.9°F (22.7°C). The temperatures fall again to descend to yearly lows in December, with highs at 56.3°F (13.5°C) and lows at 42.3°F (5.7°C).
Humidity in Sumter maintains a pretty even field from 70 to 76% throughout the year. Rainfall varies throughout the year, with January recording the least precipitation of 1.89" (48mm) and August showing the highest with 3.5" (89mm). Snowfall is minimal with meager 0.24" (6mm) in January, slowly decreasing to no snowfall from April to November, and a slight increase in December to 0.16" (4mm).
Sunshine hours, daylight hours, and UV index follow a pendular pattern. They start low in January, rise towards mid-year, and then decrease again to end the year on a lower note. Notably, maximum daylight takes place in June with 14.4 hours, subsequently dropping to 9.9 hours by year-end.
The best time to visit Sumter
For those seeking pleasant temperatures and ample sunshine, the best time to visit Sumter is from April to June. The high temperatures remain in a comfortable range from 73.4°F (23°C) to 87.4°F (30.8°C). The rainfall remains on the lower side, relative to other months, varying between 2.13" (54mm) to 3.19" (81mm). The daylight hours in this period oscillate from 13.1 hours to 14.4 hours, providing sufficient time to explore the city and engage in outdoor activities.The worst time to visit Sumter
While unfavorable periods for visiting may vary depending on individual preference, generally, July to August is considered less than ideal. This period experiences the highest temperatures with highs running between 88.9°F (31.6°C) to 90.7°F (32.6°C). Moreover, these months also have the highest rainfall for the year, with precipitation between 3.23" (82mm) to 3.5" (89mm), making outdoor activities potentially less enjoyable.Spring weather in Sumter
The spring season displays a gradual rise in temperatures in Sumter. The average temperatures in this season run from highs of 63.9°F (17.7°C) to 80.2°F (26.8°C), and lows from 46.6°F (8.1°C) to 62.8°F (17.1°C). Humidity remains relatively stable ranging between 72 to 76%. Rainfall measures from 2.13" (54mm) to 3.35" (85mm) while daylight hours increase noticeably from 12 hours in March to 13.9 hours by May end.Summer weather in Sumter
Capturing typical subtropical climate, the summer season in Sumter showcases temperature highs from 87.4°F (30.8°C) to 90.7°F (32.6°C). The minimum temperatures hover between 70°F (21.1°C) to 72.9°F (22.7°C). Rainfall peaks during this season, with measurements extending from 3.11" (79mm) to 3.5" (89mm). With more than 14 daylight hours at the onset of summer, the duration shortens slightly as the season progresses.Autumn weather in Sumter
During autumn, temperature highs range from 83.7°F (28.7°C) to 73.8°F (23.2°C), gradually decreasing from September to November. The temperature lows exhibit similar descent varying between 66.6°F (19.2°C) to 56.7°F (13.7°C). Rainfall decreases considerably during these months, ranging from 2.48" (63mm) to 1.97" (50mm). Daylight hours reduce over the course of autumn, winding down from 12.4 hours to 10.4 hours.Winter weather in Sumter
Winter brings colder temperatures to Sumter, with highs varying between 62.4°F (16.9°C) to 56.3°F (13.5°C) and lows oscillating between 46.4°F (8°C) to 42.3°F (5.7°C). Rainfall is quite variable during this season, peeking at 3.58" (91mm) in December and dipping to 1.89" (48mm) by February. Despite the cold, sunlight is relatively decent with daylight hours fluctuating from 10.4 hours to 9.9 hours.Weather in January
The new year in Sumter, South Carolina, USA, kicks off with a cool and moderately humid climate. January carries the chill of winter with an average high temperature of 52.9°F (11.6°C) and a low of 38.1°F (3.4°C). The city receives a snowfall of 0.24" (6mm) during the first month, providing a hint of a Carolina winter. Weather in January »Weather in February
Sumter transitions from January into February, anticipating an escalation in temperatures and precipitation. The month showcases a balance between winter and spring, characterized by an average high temperature of 57.7°F (14.3°C) and a low of 41°F (5°C). Weather in February »Weather in March
While February was a blend of snowflakes and rainfall, March in Sumter conveys a clear shift towards a warmer season. Plentiful sunshine and higher temperatures become predominant, marking an unequivocal arrival of spring. The highlights of this change are an average high temperature of 63.9°F (17.7°C) and a low of 46.6°F (8.1°C) accompanied by a scant snowfall of 0.04" (1mm). Weather in March »Weather in April
April is a delightful blend of distinct spring characteristics paired with emergent summer vibes. Ample daylight hours and clear skies set a bright backdrop for the blooming city of Sumter. The month's identifying features are an average high temperature of 73.4°F (23°C) and a low of 55°F (12.8°C). Weather in April »Weather in May
May greets Sumter with warmer temperatures signaling the onset of summer. The high of 80.2°F (26.8°C) and low of 62.8°F (17.1°C) hint at the rising temperatures that June will bring. With increasing humidity and ample rainfall of 3.35" (85mm), an air of fertility envelops the city. Weather in May »Weather in June
As the first official month of summer, June.Sun shines the longest with 14.4 hours of daylight and 10.5 hours of sunshine per day. Sumter’s climate reflects summer with a high temperature of 87.4°F (30.8°C) and a low of 70°F (21.1°C). Weather in June »Weather in July
July is truly the height of summer in Sumter, characterized by long days, heat, and humidity. Although the month’s average high temperature is a scorching 90.7°F (32.6°C), the low of 72.9°F (22.7°C) provides a hint of nighttime relief. Weather in July »Weather in August
August in Sumter remains hot, while the weather shows subtle indications of the impending seasonal change. The month is characterized by a high temperature of 88.9°F (31.6°C) and low of 71.4°F (21.9°C). Staying true to the trend of a Southern summer, August presents the maximum rainfall of 3.5" (89mm). Weather in August »Weather in September
September ushers in fall, bringing with it pleasant temperatures, reduced rainfall, and humidity. The gradual transition into the autumn season is seen through a high temperature of 83.7°F (28.7°C) and a low of 66.6°F (19.2°C). Weather in September »Weather in October
October, associated with a distinct autumn charm, grants Sumter a break from summer's relentless heat. The gradual lowering of the average high temperature to 73.8°F (23.2°C) and a low of 56.7°F (13.7°C) signify the onset of cooler days and nights. Weather in October »Weather in November
The last month of the autumn, November, is also an enjoyable month in Sumter, South Carolina, with an average temperature varying between 46.4°F (8°C) and 62.4°F (16.9°C). As November arrives, Sumter's weather displays a decrease in high-temperatures, transitioning from October's moderately hot 73.8°F (23.2°C) to an enjoyable 62.4°F (16.9°C). Weather in November »Weather in December
December brings the winter chill to Sumter with the year's lowest average temperatures. A high temperature of 56.3°F (13.5°C) and low of 42.3°F (5.7°C) mark this seasonal change. The month also sees a slight increase in snowfall, with 0.16" (4mm) recorded covering the city in a thin blanket of snow. Weather in December »Updated: Jul 9, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Sumter notes the coldest temperatures in January, with a average high of 52.9°F (11.6°C) and a low of 38.1°F (3.4°C).
January and November, with an average relative humidity of 70%, are the least humid months.
The month with the least rainfall is January, when the rain falls for 10.5 days and typically collects 1.89" (48mm) of precipitation.
Throughout the year, there are 161.8 rainfall days, and 33.35" (847mm) of precipitation is accumulated.
Months with snowfall in Sumter are January through March, November and December.
In Sumter, during the entire year, snow falls for 1.3 days and aggregates up to 1.06" (27mm) of snow.
The months with the lowest UV index are January, February and December, with an average maximum UV index of 3.
The month with the most snowfall in Sumter is February, when snow falls for 0.6 days and typically aggregates up to 0.55" (14mm) of snow.
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from EST to EDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from EDT to EST.
April through October are months without snowfall.
With an average relative humidity of 76%, May is the most humid month.
The month with the longest days is June, with an average of 14h and 24min of daylight.
The months with the highest UV index are June and July, with an average maximum UV index of 7.
Sumter's July weather, marked by an average high temperature of 90.7°F (32.6°C) and an average low temperature of 72.9°F (22.7°C), is the warmest in the year.
The month with the most sunshine is July, with an average of 10.7h of sunshine.
December is the month with the most rainfall. Rain falls for 11 days and accumulates 3.58" (91mm) of precipitation.
December has the shortest days of the year, with an average of 9h and 54min of daylight.
With an average of 5.3h of sunshine, December has the least sunshine of the year.
Average temperature
Sumter, SC
The warmest month (with the highest average high temperature) is July (90.7°F).
The month with the lowest average high temperature is January (52.9°F).
The month with the highest average low temperature is July (72.9°F).
The coldest month (with the lowest average low temperature) is January (38.1°F).
Average pressure
Sumter, SC
- Average pressure in January:
30.14"Hg - Average pressure in February:
30.11"Hg - Average pressure in March:
30.09"Hg - Average pressure in April:
30.02"Hg - Average pressure in May:
30.02"Hg - Average pressure in June:
29.97"Hg
- Average pressure in July:
29.99"Hg - Average pressure in August:
29.99"Hg - Average pressure in September:
30.01"Hg - Average pressure in October:
30.04"Hg - Average pressure in November:
30.14"Hg - Average pressure in December:
30.14"Hg
The months with the highest atmospheric pressure are January, November and December (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.97"Hg).
Average wind speed
Sumter, SC
- Average wind speed in January:
8mph - Average wind speed in February:
8.5mph - Average wind speed in March:
8.3mph - Average wind speed in April:
8.5mph - Average wind speed in May:
7.1mph - Average wind speed in June:
6.3mph
- Average wind speed in July:
6.2mph - Average wind speed in August:
5.6mph - Average wind speed in September:
6.3mph - Average wind speed in October:
7.1mph - Average wind speed in November:
7.1mph - Average wind speed in December:
7.5mph
The windiest months (with the highest average wind speed) are February and April (8.5mph).
The calmest month (with the lowest average wind speed) is August (5.6mph).
Average humidity
Sumter, SC
The month with the highest relative humidity is May (76%).
The months with the lowest relative humidity are January and November (70%).
Average rainfall
Sumter, SC
- Average rainfall in January:
1.89" - Average rainfall in February:
2.44" - Average rainfall in March:
2.13" - Average rainfall in April:
3.19" - Average rainfall in May:
3.35" - Average rainfall in June:
3.11"
- Average rainfall in July:
3.23" - Average rainfall in August:
3.5" - Average rainfall in September:
2.48" - Average rainfall in October:
2.48" - Average rainfall in November:
1.97" - Average rainfall in December:
3.58"
The wettest month (with the highest rainfall) is December (3.58").
The driest month (with the least rainfall) is January (1.89").
Average rainfall days
Sumter, SC
- Average rainfall days in January:
10.5 days - Average rainfall days in February:
10.8 days - Average rainfall days in March:
12.9 days - Average rainfall days in April:
13.8 days - Average rainfall days in May:
15.6 days - Average rainfall days in June:
17.1 days
- Average rainfall days in July:
20.1 days - Average rainfall days in August:
18.7 days - Average rainfall days in September:
14.1 days - Average rainfall days in October:
8.5 days - Average rainfall days in November:
8.7 days - Average rainfall days in December:
11 days
The month with the highest number of rainy days is July (20.1 days).
The month with the least rainy days is October (8.5 days).
Average snowfall
Sumter, SC
The month with the highest snowfall is February (0.55").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days
Sumter, SC
- Average snowfall days in January:
0.4 days - Average snowfall days in February:
0.6 days - Average snowfall days in March:
0.1 days - Average snowfall days in April:
0 days - Average snowfall days in May:
0 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0 days - Average snowfall days in October:
0 days - Average snowfall days in November:
0.1 days - Average snowfall days in December:
0.1 days
The month with the highest number of snowfall days is February (0.6 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight / Average sunshine
Sumter, SC
- Average daylight in January:
10h and 12min - Average daylight in February:
11h and 0min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 6min - Average daylight in May:
13h and 54min - Average daylight in June:
14h and 24min
- Average daylight in July:
14h and 12min - Average daylight in August:
13h and 24min - Average daylight in September:
12h and 24min - Average daylight in October:
11h and 18min - Average daylight in November:
10h and 24min - Average daylight in December:
9h and 54min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in January:
5h and 30min - Average sunshine in February:
6h and 24min - Average sunshine in March:
7h and 18min - Average sunshine in April:
9h and 12min - Average sunshine in May:
9h and 42min - Average sunshine in June:
10h and 30min
- Average sunshine in July:
10h and 42min - Average sunshine in August:
10h and 18min - Average sunshine in September:
8h and 42min - Average sunshine in October:
6h and 36min - Average sunshine in November:
5h and 54min - Average sunshine in December:
5h and 18min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 5h and 18min).
Average sunshine days
Sumter, SC
- Average sunshine days in January:
19.2 days - Average sunshine days in February:
16 days - Average sunshine days in March:
17.3 days - Average sunshine days in April:
14 days - Average sunshine days in May:
13.4 days - Average sunshine days in June:
10.8 days
- Average sunshine days in July:
8.8 days - Average sunshine days in August:
8.9 days - Average sunshine days in September:
13.5 days - Average sunshine days in October:
20.8 days - Average sunshine days in November:
20.5 days - Average sunshine days in December:
18.8 days
The month with the most sunshine days is October (20.8 days).
The month with the least sunshine days is July (8.8 days).
Average UV index
Sumter, SC
The months with the highest UV index are June and July (UV index 7).
The months with the lowest UV index are January, February and December (UV index 3).
Average cloud cover
Sumter, SC
The months with the most cloud cover are February and December (Cloud cover 42).
The month with the least cloud cover is October (Cloud cover 29).
Average visibility
Sumter, SC
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
