Hottest (avg)
#10 / 12
On the cooler side.
December in context
How it compares to the rest of the year in Charleston.
Wettest (avg)
#6 / 12
Typical rainfall for the year.
Daylight Hours
#12 / 12
Shorter days.
Windiest (avg)
#6 / 12
Close to the yearly wind average.
Highest UV
#12 / 12
UV is gentler than usual.
Most Humid
#5 / 12
Humidity stays close to the yearly norm.
Monthly climate breakdown
A detailed look at the typical climate conditions for December.
Thermal profile
Temperature
Typical daytime high
- Nighttime low
-
- Feels like (avg)
-
Light window
Sunshine
10 h
Average daylight
- UV index (max)
- 4
- Typical sun hours
- 07:13 - 17:15
Wet-day pattern
Rain & Snow
Typical rainfall
- Rainy days
- 10 days
- Cloud cover (avg)
- 54%
- Snowfall
-
Air feel
Humidity & Wind
76%
Average humidity
- Wind (avg)
-
- Wind (max gusts)
-
Historical daily baseline
Daily climate explorer
Pick a day to inspect the usual conditions through December in Charleston. Based on a 30-year historical climate baseline, not a forecast.
Primary control
Select a day
Scroll to compare daily conditions. The summary updates with your selection.
Secondary context
Monthly trend
Median daytime highs across the month, with a softer low line.
Median temperatureMedian lowTypical range
Day 15 selected for December. Temperature 17.4°C.
Historical disruption baseline
Typical disruptions in December
Based on 30 years of historical data, these are the disruption patterns most likely to affect plans in December.
Cold High impact
Cold feels-like nights Measures: Cold feels-like nights (min <=5C). Observed about 50% of days (15.6 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
15.6 days / month
- Share of days
- ~50% of days
- Upper edge
- Up to ~5°C (P95)
Why this matters
Cold feels-like nights are possible on ~16 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Rain High impact
Rain disruption Measures: Likely rain disruption days. Observed about 14% of days (4.4 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
4.4 days / month
- Share of days
- ~14% of days
- Upper edge
- Up to ~47mm (P95)
Why this matters
Rain disruption risk appears on ~4 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Washout risk Measures: Washout day risk. Observed about 14% of days (4.2 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
4.2 days / month
- Share of days
- ~14% of days
- Upper edge
- Up to ~49mm (P95)
Why this matters
Washout conditions are possible on ~4 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Wind High impact
Strong gusts Measures: Strong gust days (>=60 km/h). Observed about 6% of days (1.9 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.9 days / month
- Share of days
- ~6% of days
- Upper edge
- Up to ~88km/h (P95)
Why this matters
Strong gusts are possible on ~2 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Wind High impact
Stormy conditions Measures: Storm-impact proxy days. Observed about 5% of days (1.6 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.6 days / month
- Share of days
- ~5% of days
- Upper edge
- Up to ~86km/h (P95)
Why this matters
Stormy conditions are possible on ~2 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Visibility Moderate
Fog-likely signal Measures: Fog-likely visibility proxy. Observed about 6% of days (1.9 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.9 days / month
- Share of days
- ~6% of days
- Upper edge
- Up to ~97% (P95)
Why this matters
Fog-likely conditions are possible on ~2 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Show all disruptions (24 more)
Rain High impact
Heavy rain days Measures: Heavy rain days (>=10mm). Observed about 10% of days (3.0 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
3.0 days / month
- Share of days
- ~10% of days
- Upper edge
- Up to ~56mm (P95)
Why this matters
Heavy rain is possible on ~3 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Washout run Measures: Multi-day washout runs. Observed about 0.9 days/month in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.9 days / month
- Share of days
- —
- Upper edge
- Up to ~46mm (P95)
Why this matters
Multi-day washout runs are possible on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Very heavy rain Measures: Very heavy rain days (>=25mm). Observed about 3% of days (0.8 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.8 days / month
- Share of days
- ~3% of days
- Upper edge
- Up to ~85mm (P95)
Why this matters
Very heavy rain is possible on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Wind High impact
Severe gusts Measures: Severe gust days (>=80 km/h). Observed about 1% of days (0.4 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.4 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~90km/h (P95)
Why this matters
Severe gusts are possible on ~0 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Rain High impact
Extreme rain Measures: Extreme rain days (>=50mm). Observed about 1% of days (0.2 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.2 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~94mm (P95)
Why this matters
Extreme rain is possible on ~0 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Cold Moderate
Freezing nights Measures: Freezing nights (min <=0C). Observed about 3% of days (1.0 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.0 days / month
- Share of days
- ~3% of days
- Upper edge
- Up to ~-0°C (P95)
Why this matters
Freezing nights are possible on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Humidity Moderate
Muggy days Measures: Muggy days (dew point >=20C). Observed about 1% of days (0.3 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.3 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~21°C (P95)
Why this matters
Muggy conditions are possible on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cloud Minor
Cloudy days Measures: Cloudy days (cloud cover >=60%). Observed about 49% of days (15.2 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
15.2 days / month
- Share of days
- ~49% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Cloudy skies are possible on ~15 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Humidity Minor
High humidity Measures: High humidity days (RH >=80%). Observed about 46% of days (14.1 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
14.1 days / month
- Share of days
- ~46% of days
- Upper edge
- Up to ~95% (P95)
Why this matters
High humidity is possible on ~14 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Rain Minor
Wet days Measures: Wet days (>=0.1mm). Observed about 38% of days (11.9 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
11.9 days / month
- Share of days
- ~38% of days
- Upper edge
- Up to ~29mm (P95)
Why this matters
Measurable rain is possible on ~12 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Wind Minor
Gusty days Measures: Gusty days (>=40 km/h). Observed about 36% of days (11.1 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
11.1 days / month
- Share of days
- ~36% of days
- Upper edge
- Up to ~76km/h (P95)
Why this matters
Gusty conditions are possible on ~11 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Cloud Minor
Mostly cloudy days Measures: Mostly cloudy days (cloud cover >=80%). Observed about 31% of days (9.5 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
9.5 days / month
- Share of days
- ~31% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Mostly cloudy skies are possible on ~10 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Rain Minor
Rainy hours Measures: Rain-hours signal (>=3h rain). Observed about 28% of days (8.5 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
8.5 days / month
- Share of days
- ~28% of days
- Upper edge
- Up to ~20h (P95)
Why this matters
Several rainy hours are possible on ~9 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Cold Minor
Cold nights Measures: Cold nights (min <=5C). Observed about 25% of days (7.9 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
7.9 days / month
- Share of days
- ~25% of days
- Upper edge
- Up to ~5°C (P95)
Why this matters
Cold nights are possible on ~8 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Rain Minor
Wet most of day Measures: Wet-most-of-day signal (>=6h rain). Observed about 19% of days (5.9 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
5.9 days / month
- Share of days
- ~19% of days
- Upper edge
- Up to ~21h (P95)
Why this matters
Wet-most-of-day conditions are possible on ~6 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Cloud Minor
Overcast days Measures: Overcast days (cloud cover >=95%). Observed about 15% of days (4.7 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
4.7 days / month
- Share of days
- ~15% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Overcast skies are possible on ~5 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cold Minor
Cold days Measures: Cold days (max <=10C). Observed about 13% of days (4.0 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
4.0 days / month
- Share of days
- ~13% of days
- Upper edge
- Up to ~10°C (P95)
Why this matters
Cold daytime conditions are possible on ~4 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Other Minor
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data Measures: Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data. Observed about 6% of days (1.9 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.9 days / month
- Share of days
- ~6% of days
- Upper edge
- Up to ~97 (P95)
Why this matters
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data is possible on ~2 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Humidity Minor
Humid days Measures: Humid days (dew point >=18C). Observed about 4% of days (1.3 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.3 days / month
- Share of days
- ~4% of days
- Upper edge
- Up to ~21°C (P95)
Why this matters
Humid conditions are possible on ~1 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Wind Minor
Breezy days Measures: Breezy days (mean wind >=25 km/h). Observed about 3% of days (1.0 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.0 days / month
- Share of days
- ~3% of days
- Upper edge
- Up to ~34km/h (P95)
Why this matters
Breezy conditions are possible on ~1 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Cold Minor
Cold snap run Measures: Cold snap runs (>=3 cold days). Observed about 0.5 days/month in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.5 days / month
- Share of days
- —
- Upper edge
- Up to ~10°C (P95)
Why this matters
Cold snap runs are possible on ~0 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Cold Minor
Hard freeze nights Measures: Hard freeze nights (min <=-2C). Observed about 1% of days (0.4 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.4 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~-2°C (P95)
Why this matters
Hard freeze conditions are possible on ~0 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Cold Minor
Wind chill risk Measures: Wind chill risk days. Observed about 1% of days (0.3 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.3 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~-0°C (P95)
Why this matters
Wind chill risk is possible on ~0 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Humidity Minor
Convective risk Measures: Convective storm risk proxy. Observed about 1% of days (0.3 days/month) in December. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.3 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~20°C (P95)
Why this matters
Convective risk signal appears on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Travel planning FAQ
Frequently asked questions
Quick answers to the weather questions you ask the most.
Is December a good time to visit Charleston?
Typical December days in Charleston reach highs of 16°C (61°F) with nights around 9°C (48°F). It usually feels cool by day and cool after dark. Overall, December sits in the middle of the Charleston climate range.
What are temperatures like in December?
Daytime temperatures in December typically peak near 16°C (61°F), while nights drop to around 9°C (48°F). Expect cool afternoons and cool evenings.
How much does it rain in December?
Rainfall in December averages 92 mm (3.6 in) across roughly 10 days. Overall it is a quite rainy time of year, so a light rain jacket and waterproof shoes are very handy.
How many hours of daylight are there in December?
You can expect about 10 hours of daylight in December. Sunrise is typically around 07:13 and sunset near 17:15. Days are on the shorter side, so plan activities around limited daylight.
How strong is the sun in December?
UV levels are moderate (around 4); sunscreen and sunglasses are still a good idea.
Is it windy in December?
In December, average wind speeds are around 14 km/h (9 mph), with gusts on the windiest days reaching about 54 km/h (34 mph). On the ground, it is it can feel quite windy at times, particularly when weather systems move through.