São Mateus weather in December

In December, São Mateus sees average daytime highs of 27°C and overnight lows near 24°C, with 147 mm of rain across 15.5 wet days and about 13.1 hours of daylight. It is the 4th-warmest and 2nd-wettest month of the year here.

Day-to-day highs hold fairly steady near 27°C through the month. The sky is clear or mostly clear about 26% of the time in December, and the air most often feels oppressive.

Daylight stretches from about 13 hours at the start of December to 13 h 06 min by month's end. Set against the rest of the year, December is São Mateus's 11th-clearest and 4th-windiest month. For the whole year in context, see São Mateus's year-round climate.

Daytime high
27°
4th warmest
Overnight low
24°
9th coldest
Rainfall
147 mm
15.5 wet days
Daylight
13 h 06 min
6:02 AM – 7:09 PM
Cloud cover
66%
11th clearest
Wind
18 km/h
4th windiest
Solar energy
6.35 kWh/m²
Travel score
5.5
out of 10

São Mateus is human settlement in Brazil.

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

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 27°C through the month.

A typical December day in São Mateus reaches about 27°C in the afternoon and slips back to 24°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 26°C and 29°C. Set against its neighbours, December runs about 1°C warmer than November and on par with January.

20°23°25°28°30°151015202531
Avg high (°C)Avg low (°C)
12724
22724
32724
42724
52724
62724
72724
82724
92724
102724
112724
122724
132724
142724
152724
162724
172724
182824
192824
202824
212824
222824
232824
242824
252824
262824
272824
282824
292824
302824
312824

São Mateus weather by month

How December compares with the rest of the year at a glance. December is the 4th-warmest and 2nd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 24°10613.4135.9
Feb28° / 24°7613.912.65.4
Mar28° / 24°13618.212.15.2
Apr27° / 24°10816.911.65.6
May26° / 22°7013.211.16.4
Jun25° / 21°5211.810.96.8
Jul24° / 21°5713.2116.8
Aug24° / 21°4811.211.47.1
Sep25° / 22°5410.811.96.9
Oct26° / 23°9613.412.46.2
Nov26° / 23°18317.612.95.3
Dec27° / 24°14715.513.15.5

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 26% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 13% of December, with mostly cloudy or overcast conditions the remaining 61%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13169
23169
33169
43169
53268
63268
73268
83367
93367
103367
113466
123565
133664
143763
153862
164060
174159
184159
194258
204357
214456
224456
234555
244555
254654
264654
274654
284654
294654
304555
314555

Chance of precipitation in December

Any precipitation

São Mateus gets around 147 mm of rain over 15.5 wet days in December. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 50% and peaks near 61% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202531
Rain chance (%)
161
260
359
459
558
657
756
856
955
1054
1153
1252
1351
1451
1550
1649
1748
1847
1947
2046
2146
2245
2345
2444
2544
2643
2743
2843
2943
3043
3143

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, December lands in the oppressive band about 90% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1216793
2115813
3114823
4114823
5113833
6112843
7111844
8110854
919864
1008884
1107903
1206913
1305923
1405923
1504933
1604933
1703943
1803943
1903943
2003943
2102953
2202953
2302953
2403943
2503943
2603934
2703934
2803934
2903934
3003925
3103925

Wind in December

Winds average 18 km/h in December.

Across December, daily wind ranges from about 18 km/h on the calmest days to 19 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202531
Wind speed (km/h)Feels
119light breeze
219light breeze
318light breeze
418light breeze
518light breeze
618light breeze
718light breeze
818light breeze
918light breeze
1018light breeze
1118light breeze
1218light breeze
1318light breeze
1418light breeze
1518light breeze
1618light breeze
1718light breeze
1818light breeze
1918light breeze
2018light breeze
2118light breeze
2218light breeze
2318light breeze
2418light breeze
2518light breeze
2618light breeze
2718light breeze
2818light breeze
2918light breeze
3018light breeze
3118light breeze

Sunrise & sunset in December

DaylightNight

Daylight runs from about 13 hours at the start of December to 13 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 6 minutes over December. Sunrise moves from 5:58 AM to 6:09 AM, and sunset from 7:01 PM to 7:16 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:587:01
213.15:587:01
313.15:587:02
413.15:587:02
513.15:597:03
613.15:597:04
713.15:597:04
813.15:597:05
913.16:007:05
1013.16:007:06
1113.16:007:06
1213.16:017:07
1313.16:017:08
1413.16:017:08
1513.16:027:09
1613.16:027:09
1713.16:027:10
1813.16:037:10
1913.16:037:11
2013.16:047:11
2113.16:047:12
2213.16:057:12
2313.16:057:13
2413.16:067:13
2513.16:067:14
2613.16:077:14
2713.16:077:14
2813.16:087:15
2913.16:087:15
3013.16:097:16
3113.16:097:16

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 6.35 kWh/m².

For context, solar energy here swings from a low near 3.83 kWh/m² to a high of 6.76 kWh/m² in January across the year — December's 6.35 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.9Bright
25.9Bright
36.0Bright
46.0Bright
56.0Intense
66.0Intense
76.1Intense
86.1Intense
96.1Intense
106.2Intense
116.2Intense
126.2Intense
136.3Intense
146.3Intense
156.3Intense
166.4Intense
176.4Intense
186.5Intense
196.5Intense
206.5Intense
216.5Intense
226.6Intense
236.6Intense
246.6Intense
256.6Intense
266.6Intense
276.7Intense
286.7Intense
296.7Intense
306.7Intense
316.7Intense
Planning a trip in December

Is December a good time to visit São Mateus?

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

5.5
Sightseeing
9th-best month of the year
5.8
Beach & pool
9th-best month of the year

December is a reasonable time to visit São Mateus for sightseeing.

What to pack for São Mateus in December

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

In December, São Mateus sees daytime highs around 27°C and nights near 24°C. Pack light clothes, rain gear and sun protection. About 16 days see rain.

light clothesrain gearsun protection

Sea temperature near São Mateus in December

The nearest coast averages about 26°C in December — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 27 km away) is warmest in March at about 28°C and coldest in August near 24°C.

The water stays above 20°C all year — warm enough for a swim any month.

22°24°26°28°JanFebMarAprMayJunJulAugSepOctNovDecrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan27Warm
Feb27Warm
Mar28Warm
Apr27Warm
May26Warm
Jun25Warm
Jul24Warm
Aug24Warm
Sep25Warm
Oct25Warm
Nov26Warm
Dec26Warm

UV index in São Mateus in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 13 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in São Mateus peaks around February 13 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 20 at about 7 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highHighVery highExtremeFeb 13UV 14Jun 20UV 7
UV index (midday)Level
Jan14Extreme
Feb15Extreme
Mar13Extreme
Apr10Extreme
May8Very high
Jun7High
Jul7High
Aug9Very high
Sep10Extreme
Oct12Extreme
Nov14Extreme
Dec13Extreme
Location & terrain

Where is São Mateus?

São Mateus sits at 18.7°S, 39.9°W, 38 m above sea level, in Brazil. The nearest listed city is Conceição da Barra, 19 km away.

Topography around São Mateus

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of São Mateus.

Within 3 km, the terrain around São Mateus has only modest variations in elevation — a maximum elevation change of 51 m around an average of 22 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 95 m; within 80 km, large variations in elevation — a maximum elevation change of 744 m.

The land around São Mateus is covered by trees (34%), artificial surfaces (26%) and grassland (21%) within 3 km, trees (55%) and grassland (26%) within 16 km, and grassland (37%), trees (33%) and water (27%) within 80 km.

3 km
51 m
16 km
95 m
80 km
744 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
December weather nearby: Conceição da Barra 19 km · Jaguaré 31 km · Pinheiros 54 km · Nova Venécia 57 km · Sooretama 59 km · Mucuri 78 km · Linhares 78 km · Rio Bananal 78 km

Brazil travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / N
127 / 220 V · 60 Hz
Prices
≈ 46% of US
price level, 2025
GDP per capita
$10,713
2025
Happiness
6.6 / 10
World Happiness, 2025
Safe drinking water
89%
of population, 2024
Homicide rate
19.3
per 100k, 2023
Road deaths
16
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Low
EF EPI 482
Religion
Roman Catholic 57%Evangelical 27%none 9%other 4%

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 São Mateus (-18.7201°, -39.8589°, elevation 38 m), 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. 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).