Sebastian weather in December

In December, Sebastian sees average daytime highs of 74°F and overnight lows near 60°F, with 1.5 in of rain across 5.6 wet days and about 10.3 hours of daylight. It is the 11th-warmest and 12th-wettest month of the year here.

Highs ease over the month, from about 76°F in the first days to 73°F by the end. The sky is clear or mostly clear about 31% of the time in December, and the air most often feels dry.

Daylight stretches from about 10 h 24 min at the start of December to 10 h 18 min by month's end. Set against the rest of the year, December is Sebastian's 6th-clearest and 6th-windiest month. For the whole year in context, see Sebastian's year-round climate.

Daytime high
74°
11th warmest
Overnight low
60°
3rd coldest
Rainfall
1.5 in
5.6 wet days
Daylight
10 h 12 min
7:11 AM – 5:25 PM
Cloud cover
57%
6th clearest
Wind
8 mph
6th windiest
Solar energy
3.05 kWh/m²
Travel score
7.5
out of 10

Sebastian is city in Indian River County, State of Florida, United States.

Density
637/km²
people per km²
Founded
1882

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 76°F in the first days to 73°F by the end.

A typical December day in Sebastian reaches about 74°F in the afternoon and slips back to 60°F overnight — a 14°F spread between the day's warmth and the night's chill. On most days the high lands between 64°F and 81°F. Set against its neighbours, December runs about 4°F cooler than November and about 2°F warmer than January.

40°50°60°70°80°151015202531
Avg high (°F)Avg low (°F)
17662
27662
37662
47562
57562
67562
77561
87561
97561
107561
117461
127461
137460
147460
157460
167460
177460
187460
197360
207359
217359
227359
237359
247359
257359
267359
277359
287358
297358
307358
317358

How December really feels in Sebastian

Once humidity and wind are folded in, December averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

December sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Sebastian weather by month

How December compares with the rest of the year at a glance. December is the 11th-warmest and 12th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan72° / 57°2.06.910.47.2
Feb74° / 58°1.77117.4
Mar78° / 62°2.27.611.87.3
Apr82° / 67°2.17.712.66.6
May85° / 72°3.211.313.45.1
Jun88° / 75°7.221.413.73.2
Jul89° / 77°6.723.213.62.8
Aug89° / 77°7.224.9132.7
Sep87° / 76°6.221.412.23.4
Oct83° / 72°3.712.711.35.5
Nov78° / 65°1.67.510.67.2
Dec74° / 60°1.55.610.37.5

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 31% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 18% of December, with mostly cloudy or overcast conditions the remaining 51%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15644
25644
35644
45545
55545
65446
75446
85347
95347
105248
115248
125149
135149
144951
154951
164852
174753
184654
194555
204456
214456
224456
234357
244357
254357
264357
274357
284357
294555
304555
314654

Chance of precipitation in December

Any precipitation

Sebastian gets around 1.5 in of rain over 5.6 wet days in December, the driest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 19% and peaks near 20% on the wettest days.

0%10%20%30%151015202531
Rain chance (%)
119
219
319
419
519
619
719
819
919
1019
1119
1219
1319
1419
1519
1619
1719
1819
1919
2018
2118
2218
2318
2418
2519
2619
2719
2820
2920
3020
3120

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

Most of December feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, December lands in the dry band about 34% of days. Sticky, muggy-or-worse air turns up on roughly 26% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1271928225
2271828225
3281728225
4281728235
5281627235
6291627245
7291527245
8301526255
9301526254
10311525254
11311525254
12321525254
13331524244
14331524244
15341523244
16351523234
17361522234
18371522224
19371522224
20381522214
21391522214
22391522204
23391522204
24391521204
25391522204
26391522204
27391522204
28391522204
29391522194
30391522194
31401522194

Wind in December

Winds average 8 mph in December.

Across December, daily wind ranges from about 8 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
18light breeze
28light breeze
38light breeze
48light breeze
58light breeze
68light breeze
78light breeze
88light breeze
98light breeze
108light breeze
118light breeze
128light breeze
138light breeze
148light breeze
158light breeze
168light breeze
178light breeze
188light breeze
198light breeze
208light breeze
218light breeze
228light breeze
238light breeze
248light breeze
258light breeze
268light breeze
278light breeze
288light breeze
298light breeze
308light breeze
318light breeze

Sunrise & sunset in December

DaylightNight

Daylight runs from about 10 h 24 min at the start of December to 10 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 6 minutes over December. Sunrise moves from 7:01 AM to 7:17 AM, and sunset from 5:23 PM to 5:33 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
110.47:015:23
210.47:015:23
310.37:025:23
410.37:035:23
510.37:045:23
610.37:045:23
710.37:055:23
810.37:065:23
910.37:065:23
1010.37:075:24
1110.37:085:24
1210.37:085:24
1310.37:095:24
1410.37:095:25
1510.37:105:25
1610.27:115:25
1710.27:115:26
1810.27:125:26
1910.27:125:27
2010.27:135:27
2110.27:135:27
2210.27:145:28
2310.27:145:28
2410.27:155:29
2510.27:155:29
2610.27:155:30
2710.27:165:31
2810.27:165:31
2910.37:175:32
3010.37:175:32
3110.37:175:33

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 3.05 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 3.05 kWh/m² to a high of 6.39 kWh/m² in May across the year — December's 3.05 kWh/m² sits near the bottom.

01234151015202531
Solar energy (kWh/m²)Level
13.2Moderate
23.2Moderate
33.2Moderate
43.1Moderate
53.1Moderate
63.1Moderate
73.1Moderate
83.1Moderate
93.1Moderate
103.1Moderate
113.1Moderate
123.0Moderate
133.0Moderate
143.0Moderate
153.0Moderate
163.0Moderate
173.0Moderate
183.0Moderate
193.0Moderate
203.0Moderate
213.0Moderate
223.0Moderate
233.0Moderate
243.0Moderate
253.0Moderate
263.0Moderate
273.0Moderate
283.0Moderate
293.1Moderate
303.1Moderate
313.1Moderate
Planning a trip in December

Hazard calendar for Sebastian

In seasonPeak

None of Sebastian's seasonal hazards are active in December. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Sebastian sits in the Atlantic hurricane belt; the season peaks August–October.

Sebastian's monsoon runs June–October, when most of the year's rain falls.

Atlantic hurricane
Monsoon
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is December a good time to visit Sebastian?

Our two travel scores rate December for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

7.5
Sightseeing
1st-best month of the year
6.0
Beach & pool
6th-best month of the year

December is one of the better times to visit Sebastian for general sightseeing.

What to pack for Sebastian in December

From December's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In December, Sebastian sees daytime highs around 74°F and nights near 60°F. Worth packing: light clothes. About 6 days see rain.

light clothes

Sea temperature near Sebastian in December

The nearest coast averages about 73°F in December — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in September at about 83°F and coldest in February near 70°F.

The water stays above 68°F all year — warm enough for a swim any month.

70°75°80°85°JanFebMarAprMayJunJulAugSepOctNovDeccoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°F)Comfort
Jan70Refreshing
Feb70Refreshing
Mar71Refreshing
Apr74Refreshing
May77Warm
Jun80Warm
Jul82Warm
Aug82Warm
Sep83Tropical
Oct81Warm
Nov76Warm
Dec73Refreshing

UV index in Sebastian in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Sebastian peaks around July 14 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 4 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecHighVery highExtremeVery highHighModerateJul 14UV 11Dec 19UV 4
UV index (midday)Level
Jan5Moderate
Feb7High
Mar9Very high
Apr8Very high
May10Very high
Jun11Extreme
Jul11Extreme
Aug10Extreme
Sep9Very high
Oct7Very high
Nov5High
Dec4Moderate

Air quality in Sebastian in December

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where December falls, not just the annual average.

Air quality in Sebastian is worst in July — around 17 µg/m³ PM2.5 (moderate), about 3.1× the cleanest month (December, 6 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1817 µg/m³Dec 156 µg/m³
PM2.5 (µg/m³)Level
Jan6Good
Feb7Good
Mar9Good
Apr10Good
May10Good
Jun14Moderate
Jul17Moderate
Aug15Moderate
Sep10Good
Oct8Good
Nov6Good
Dec6Good
Location & terrain

Where is Sebastian?

Sebastian sits at 27.8°N, 80.5°W, 20 ft above sea level, in United States. The nearest listed city is Vero Beach, 13 mi away.

Topography around Sebastian

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Sebastian.

Within 2 miles, the terrain around Sebastian has only modest variations in elevation — a maximum elevation change of 43 ft around an average of 13 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 82 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 246 ft.

The land around Sebastian is covered by water (44%) and trees (28%) within 2 miles, water (45%), trees (28%) and grassland (21%) within 10 miles, and water (37%), grassland (32%) and trees (25%) within 50 miles.

2 miles
43 ft
10 miles
82 ft
50 miles
246 ft
treesgrasslandcroplandartificial surfaceswaterwetlandmangroves
December weather nearby: Vero Beach 13 mi · Vero Beach South 14 mi · Palm Bay 17 mi · Florida Ridge 17 mi · Melbourne 21 mi · West Melbourne 21 mi · Fort Pierce 27 mi · Port Saint Lucie 37 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Sebastian (27.8164°, -80.4706°, elevation 20 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).