Climate and monthly weather forecastSullivan's Island, SC
Climate and monthly weather forecast
Weather in January
January, the same as December, in Sullivan's Island, South Carolina, is another mild winter month, with an average temperature ranging between max 57°F (13.9°C) and min 45.5°F (7.5°C). January is the coldest month, with the temperature often reaching an average high of 57°F (13.9°C) and an average low of 45.5°F (7.5°C). Weather in January »Weather in February
The last month of the winter, February, is another refreshing month in Sullivan's Island, South Carolina, with an average temperature fluctuating between 48.7°F (9.3°C) and 59.9°F (15.5°C). February commences with an average high-temperature of a still moderate 59.9°F (15.5°C), showing little deviation from January's 57°F (13.9°C). Weather in February »Weather in March
The first month of the spring, March, is an enjoyable month in Sullivan's Island, South Carolina, with an average temperature varying between 64.4°F (18°C) and 53.6°F (12°C). March experiences an average high-temperature of an enjoyable 64.4°F (18°C), barely different from February's 59.9°F (15.5°C). Weather in March »Weather in April
April in Sullivan's Island, South Carolina, is an agreeable spring month, with temperature in the range of an average high of 71.8°F (22.1°C) and an average low of 61.3°F (16.3°C). Sullivan's Island in April experiences a slight uptick in the average high-temperature, adjusting from March's enjoyable 64.4°F (18°C) to an agreeable 71.8°F (22.1°C). Weather in April »Weather in May
The last month of the spring, May, is a warm month in Sullivan's Island, South Carolina, with temperature in the range of an average high of 78.1°F (25.6°C) and an average low of 68.7°F (20.4°C). Sullivan's Island's weather shows a minor temperature rise with the arrival of May, moving from a pleasant 71.8°F (22.1°C) in April to a warm 78.1°F (25.6°C). Weather in May »Weather in June
June, the first month of the summer in Sullivan's Island, is also a moderately hot month, with an average temperature varying between 75.4°F (24.1°C) and 84.6°F (29.2°C). Sullivan's Island observes a slight ascent in average high-temperatures during June, adjusting from 78.1°F (25.6°C) in May to a still moderately hot 84.6°F (29.2°C). Weather in June »Weather in July
July is a tropical summer month in Sullivan's Island, South Carolina, with temperature in the range of an average low of 78.3°F (25.7°C) and an average high of 86.5°F (30.3°C). In Sullivan's Island, the month of July registers the highest temperatures, averaging 86.5°F (30.3°C) at the peak and 78.3°F (25.7°C) at the lowest. July's average heat index is appraised at a very hot 98.6°F (37°C). Weather in July »Weather in August
The last month of the summer, August, is also a moderately hot month in Sullivan's Island, South Carolina, with an average temperature ranging between min 78.1°F (25.6°C) and max 85.8°F (29.9°C). The average high-temperature is a moderately hot 85.8°F (29.9°C) in August, hardly different from the 86.5°F (30.3°C) recorded in July. Weather in August »Weather in September
The first month of the autumn, September, is also a moderately hot month in Sullivan's Island, South Carolina, with an average temperature ranging between min 74.3°F (23.5°C) and max 82.9°F (28.3°C). As August turns into September, the average high-temperatures rest at a still warm 82.9°F (28.3°C), showing a minor variation from the prior month. Weather in September »Weather in October
October, like September, in Sullivan's Island, South Carolina, is another warm autumn month, with an average temperature fluctuating between 64.9°F (18.3°C) and 75.2°F (24°C). Start of October brings a slight shift in the average high-temperature, dipping a bit from September's 82.9°F (28.3°C) to a still moderately hot 75.2°F (24°C). Weather in October »Weather in November
November, the last month of the autumn in Sullivan's Island, is another comfortable month, with temperature in the range of an average low of 54.9°F (12.7°C) and an average high of 65.7°F (18.7°C). With November's onset, the average high-temperature recedes from October's warm 75.2°F (24°C) to an enjoyable 65.7°F (18.7°C). Weather in November »Weather in December
The first month of the winter, December, is also an enjoyable month in Sullivan's Island, South Carolina, with an average temperature varying between 50.4°F (10.2°C) and 61°F (16.1°C). The advent of December reveals an average high-temperature of a still enjoyable 61°F (16.1°C), showing minimal difference from the prior month. Weather in December »Updated: Jul 4, 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
The lowest temperatures are recorded in January, with averages reaching a high of 57°F (13.9°C) and a low of 45.5°F (7.5°C).
The months with the lowest humidity are January and March, with an average relative humidity of 73%.
January is the month with the least rainfall. Rain falls for 9.7 days and accumulates 1.42" (36mm) of precipitation.
In Sullivan's Island, during the entire year, the rain falls for 182 days and collects up to 45.55" (1157mm) of precipitation.
January and February are months with snowfall in Sullivan's Island.
January has the most snowfall days of the year in Sullivan's Island. Snow falls for 0.3 days.
Throughout the year, there are 0.4 snowfall days.
The month with the lowest UV index is January, with an average maximum UV index of 3.
In Sullivan's Island, snow does not fall in March through December.
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.
The months with the highest UV index are May through August, with an average maximum UV index of 7.
The month with the longest days is June, with an average of 14h and 18min of daylight.
In Sullivan's Island, July is identified by the average highest temperatures, reaching a peak of 86.5°F (30.3°C) and a low of 78.3°F (25.7°C).
The month with the most sunshine is July, with an average of 11h of sunshine.
August is the month with the most rainfall. Rain falls for 25.9 days and accumulates 8.23" (209mm) of precipitation.
The most humid month in Sullivan's Island is December, with an average relative humidity of 78%.
The month with the shortest days is December, with an average of 10h and 0min of daylight.
The month with the least sunshine is December, with an average of 5.7h of sunshine.
Average temperature
Sullivan's Island, SC
The warmest month (with the highest average high temperature) is July (86.5°F).
The month with the lowest average high temperature is January (57°F).
The month with the highest average low temperature is July (78.3°F).
The coldest month (with the lowest average low temperature) is January (45.5°F).
Average pressure
Sullivan's Island, 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:
30.03"Hg - Average pressure in May:
30.03"Hg - Average pressure in June:
29.98"Hg
- Average pressure in July:
30"Hg - Average pressure in August:
29.99"Hg - Average pressure in September:
30"Hg - Average pressure in October:
30.02"Hg - Average pressure in November:
30.12"Hg - Average pressure in December:
30.12"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.98"Hg).
Average wind speed
Sullivan's Island, SC
- Average wind speed in January:
10mph - Average wind speed in February:
10.2mph - Average wind speed in March:
10.3mph - Average wind speed in April:
10.3mph - Average wind speed in May:
9.4mph - Average wind speed in June:
8.9mph
- Average wind speed in July:
9.1mph - Average wind speed in August:
8.4mph - Average wind speed in September:
9.2mph - Average wind speed in October:
9.5mph - Average wind speed in November:
9.8mph - Average wind speed in December:
9.8mph
The windiest months (with the highest average wind speed) are March and April (10.3mph).
The calmest month (with the lowest average wind speed) is August (8.4mph).
Average humidity
Sullivan's Island, SC
The month with the highest relative humidity is December (78%).
The months with the lowest relative humidity are January and March (73%).
Average rainfall
Sullivan's Island, SC
- Average rainfall in January:
1.42" - Average rainfall in February:
2.01" - Average rainfall in March:
1.97" - Average rainfall in April:
3.07" - Average rainfall in May:
3.23" - Average rainfall in June:
4.72"
- Average rainfall in July:
5.67" - Average rainfall in August:
8.23" - Average rainfall in September:
5.71" - Average rainfall in October:
3.23" - Average rainfall in November:
2.01" - Average rainfall in December:
4.29"
The wettest month (with the highest rainfall) is August (8.23").
The driest month (with the least rainfall) is January (1.42").
Average rainfall days
Sullivan's Island, SC
- Average rainfall days in January:
9.7 days - Average rainfall days in February:
10.7 days - Average rainfall days in March:
11.5 days - Average rainfall days in April:
13.1 days - Average rainfall days in May:
15.8 days - Average rainfall days in June:
21 days
- Average rainfall days in July:
24.4 days - Average rainfall days in August:
25.9 days - Average rainfall days in September:
19.2 days - Average rainfall days in October:
11.7 days - Average rainfall days in November:
8.5 days - Average rainfall days in December:
10.5 days
The month with the highest number of rainy days is August (25.9 days).
The month with the least rainy days is November (8.5 days).
Average snowfall days
Sullivan's Island, SC
- Average snowfall days in January:
0.3 days - Average snowfall days in February:
0.1 days - Average snowfall days in March:
0 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 days - Average snowfall days in December:
0 days
The month with the highest number of snowfall days is January (0.3 days).
The months with the least snowfall days are March, April, May, June, July, August, September, October, November and December (0 days).
Average daylight / Average sunshine
Sullivan's Island, SC
- Average daylight in January:
10h and 18min - Average daylight in February:
11h and 0min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 0min - Average daylight in May:
13h and 54min - Average daylight in June:
14h and 18min
- Average daylight in July:
14h and 6min - Average daylight in August:
13h and 18min - Average daylight in September:
12h and 24min - Average daylight in October:
11h and 24min - Average daylight in November:
10h and 30min - Average daylight in December:
10h and 0min
The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in January:
5h and 48min - Average sunshine in February:
6h and 48min - Average sunshine in March:
7h and 48min - Average sunshine in April:
9h and 54min - Average sunshine in May:
10h and 30min - Average sunshine in June:
10h and 54min
- Average sunshine in July:
11h and 0min - Average sunshine in August:
10h and 48min - Average sunshine in September:
9h and 12min - Average sunshine in October:
6h and 42min - Average sunshine in November:
6h and 6min - Average sunshine in December:
5h and 42min
The month with the most sunshine is July (Average sunshine: 11h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).
Average sunshine days
Sullivan's Island, SC
- Average sunshine days in January:
19.3 days - Average sunshine days in February:
15.8 days - Average sunshine days in March:
17.7 days - Average sunshine days in April:
15.8 days - Average sunshine days in May:
12.7 days - Average sunshine days in June:
6.5 days
- Average sunshine days in July:
4.1 days - Average sunshine days in August:
2.8 days - Average sunshine days in September:
7.9 days - Average sunshine days in October:
18.1 days - Average sunshine days in November:
19.1 days - Average sunshine days in December:
18.5 days
The month with the most sunshine days is January (19.3 days).
The month with the least sunshine days is August (2.8 days).
Average UV index
Sullivan's Island, SC
The months with the highest UV index are May, June, July and August (UV index 7).
The month with the lowest UV index is January (UV index 3).
Average cloud cover
Sullivan's Island, SC
The month with the most cloud cover is December (Cloud cover 39).
The month with the least cloud cover is June (Cloud cover 25).
Average visibility
Sullivan's Island, 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).
