Reforma weather in December

In December, Reforma sees average daytime highs of 27°C and overnight lows near 20°C, with 106 mm of rain across 11.6 wet days and about 10.9 hours of daylight. It is the 11th-warmest and 8th-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 33% of the time in December, and the air most often feels oppressive.

Daylight stretches from about 11 hours at the start of December to 10 h 54 min by month's end. Set against the rest of the year, December is Reforma's 5th-clearest and 6th-windiest month. For the whole year in context, see Reforma's year-round climate.

Daytime high
27°
11th warmest
Overnight low
20°
3rd coldest
Rainfall
106 mm
11.6 wet days
Daylight
10 h 54 min
6:41 AM – 5:37 PM
Cloud cover
55%
5th clearest
Wind
8 km/h
6th windiest
Solar energy
3.58 kWh/m²
Travel score
6.2
out of 10

Reforma is municipal seat of Reforma, State of Chiapas, Mexico.

Founded
1883

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 Reforma reaches about 27°C in the afternoon and slips back to 20°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 24°C and 31°C. Set against its neighbours, December runs about 1°C cooler than November and on par with January.

15°20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
12820
22820
32820
42820
52820
62820
72820
82820
92820
102820
112820
122820
132720
142720
152720
162720
172720
182720
192720
202720
212720
222720
232720
242720
252720
262720
272719
282719
292719
302719
312719

How December really feels in Reforma

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

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
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.

Reforma weather by month

How December compares with the rest of the year at a glance. December is the 11th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan27° / 19°11511.4116.4
Feb28° / 20°788.811.46.1
Mar31° / 21°486.611.95.1
Apr34° / 23°516.612.43.6
May34° / 25°8210.512.82.8
Jun34° / 25°18119.3132.4
Jul34° / 25°11816.2132.6
Aug33° / 24°18721.912.62.4
Sep32° / 24°24924.812.12.6
Oct30° / 23°23420.211.63.7
Nov29° / 21°15414.711.25.1
Dec27° / 20°10611.610.96.2

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 33% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 20% of December, with mostly cloudy or overcast conditions the remaining 47%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15743
25743
35743
45743
55743
65743
75743
85743
95743
105644
115545
125545
135446
145446
155446
165347
175347
185248
195248
205149
215149
225149
235050
245050
254951
264951
274951
284852
294852
304753
314852

Chance of precipitation in December

Any precipitation

Reforma gets around 106 mm of rain over 11.6 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 38% and peaks near 41% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
141
241
341
440
540
639
739
838
938
1038
1137
1237
1336
1436
1536
1636
1736
1836
1936
2036
2137
2237
2338
2438
2539
2639
2740
2840
2941
3041
3141

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 44% of days. Sticky, muggy-or-worse air turns up on roughly 88% of them.

0%25%50%75%100%151015202531
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
11737541
21738531
31738531
41739521
51739521
61839511
71839511
81839511
91940501
101940491
1111040481
1211041471
1311141461
1411141461
1511242451
1621242441
1721343421
1821343411
1921344401
2021445391
2121446381
2221447371
2321447370
2421448360
2521448360
2621449360
2721449360
2821449350
2921449350
3021549350
3121549340

Wind in December

Winds average 8 km/h in December.

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

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

Sunrise & sunset in December

DaylightNight

Daylight runs from about 11 hours at the start of December to 10 h 54 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 6:32 AM to 6:47 AM, and sunset from 5:33 PM to 5:44 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
111.06:325:33
211.06:335:33
311.06:335:33
411.06:345:33
511.06:355:33
611.06:355:34
711.06:365:34
811.06:365:34
911.06:375:34
1011.06:375:35
1111.06:385:35
1210.96:395:35
1310.96:395:36
1410.96:405:36
1510.96:405:36
1610.96:415:37
1710.96:415:37
1810.96:425:38
1910.96:425:38
2010.96:435:39
2110.96:435:39
2210.96:445:39
2310.96:445:40
2410.96:455:40
2510.96:455:41
2610.96:465:41
2710.96:465:42
2810.96:465:42
2910.96:475:43
3010.96:475:44
3110.96:475:44

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 3.58 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 3.58 kWh/m² to a high of 6.38 kWh/m² in April across the year — December's 3.58 kWh/m² sits near the bottom.

01234151015202531
Solar energy (kWh/m²)Level
13.7Moderate
23.7Moderate
33.7Moderate
43.7Moderate
53.7Moderate
63.6Moderate
73.6Moderate
83.6Moderate
93.6Moderate
103.6Moderate
113.6Moderate
123.6Moderate
133.6Moderate
143.5Moderate
153.5Moderate
163.5Moderate
173.5Moderate
183.5Moderate
193.5Moderate
203.5Moderate
213.5Moderate
223.5Moderate
233.5Moderate
243.5Moderate
253.5Moderate
263.5Moderate
273.5Moderate
283.5Moderate
293.5Moderate
303.5Moderate
313.5Moderate
Planning a trip in December

Hazard calendar for Reforma

In seasonPeak

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

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

Reforma's rainy season runs January–January, when most of the year's rain falls.

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

Is December a good time to visit Reforma?

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

6.2
Sightseeing
2nd-best month of the year
6.5
Beach & pool
4th-best month of the year

December is a reasonable time to visit Reforma for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Reforma in December

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

In December, Reforma sees daytime highs around 27°C and nights near 20°C. Pack light clothes. Worth having: rain gear. About 12 days see rain.

light clothesrain gear

UV index in Reforma in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Reforma peaks around June 20 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near January 10 at about 7 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecVery highExtremeVery highExtremeVery highJun 20UV 12Jan 10UV 7
UV index (midday)Level
Jan7High
Feb10Extreme
Mar12Extreme
Apr13Extreme
May7Very high
Jun13Extreme
Jul11Extreme
Aug13Extreme
Sep11Extreme
Oct10Extreme
Nov8Very high
Dec7High

Air quality in Reforma 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 Reforma is worst in May — around 77 µg/m³ PM2.5 (unhealthy), about 2.4× the cleanest month (January, 32 µg/m³).

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

020406080JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorUnhealthyPoorMay 1375 µg/m³Jan 1633 µg/m³
PM2.5 (µg/m³)Level
Jan32Moderate
Feb37Poor
Mar46Poor
Apr69Unhealthy
May77Unhealthy
Jun52Poor
Jul45Poor
Aug40Poor
Sep41Poor
Oct38Poor
Nov36Poor
Dec37Poor
Location & terrain

Where is Reforma?

Reforma sits at 17.9°N, 93.2°W, 27 m above sea level, in Mexico. The nearest listed city is Cunduacán, 23 km away.

Topography around Reforma

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

Within 3 km, the terrain around Reforma has only modest variations in elevation — a maximum elevation change of 40 m around an average of 26 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 81 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,423 m.

The land around Reforma is covered by grassland (59%) and trees (23%) within 3 km, grassland (71%) and trees (24%) within 16 km, and grassland (44%) and trees (33%) within 80 km.

3 km
40 m
16 km
81 m
80 km
2,423 m
treesgrasslandcroplandartificial surfaceswaterwetlandmangroves
December weather nearby: Cunduacán 23 km · Playas del Rosario 23 km · Huimanguillo 25 km · Villahermosa 27 km · Río de Teapa 28 km · Cárdenas 28 km · Taxco 35 km · Jalpa de Méndez 37 km

Mexico travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type A / B
120 / 127 V · 60 Hz
Prices
≈ 54% of US
price level, 2025
GDP per capita
$13,889
2025
Happiness
7.0 / 10
World Happiness, 2025
Safe drinking water
43%
of population, 2024
Homicide rate
24.9
per 100k, 2023
Road deaths
12.8
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Very low
EF EPI 440
Religion
Catholic 78%no religion 11%other Evangelical Churches 8%Jehovah Witness 1%

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 Reforma (17.859°, -93.1538°, elevation 27 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).