União weather in January

In January, União sees average daytime highs of 33°C and overnight lows near 24°C, with 228 mm of rain across 21.8 wet days and about 12.2 hours of daylight. It is the 8th-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 33°C through the month. The sky is clear or mostly clear about 10% of the time in January, and the air most often feels oppressive.

Daylight stretches from about 12 h 18 min at the start of January to 12 h 12 min by month's end. Set against the rest of the year, January is União's 9th-clearest and 8th-windiest month. For the whole year in context, see União's year-round climate.

Daytime high
33°
8th warmest
Overnight low
24°
8th coldest
Rainfall
228 mm
21.8 wet days
Daylight
12 h 12 min
5:54 AM – 6:08 PM
Cloud cover
75%
9th clearest
Wind
6 km/h
8th windiest
Solar energy
5.13 kWh/m²
Travel score
2.6
out of 10

União is settlement in Uniao, Piaui, Brazil.

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

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 33°C through the month.

A typical January day in União reaches about 33°C in the afternoon and slips back to 24°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 29°C and 36°C. Set against its neighbours, January runs about 3°C cooler than December and about 1°C warmer than February.

20°25°30°35°40°151015202531
Avg high (°C)Avg low (°C)
13424
23424
33424
43324
53324
63324
73324
83324
93324
103324
113324
123324
133324
143324
153224
163224
173224
183224
193224
203224
213224
223224
233224
243224
253224
263224
273224
283224
293224
303224
313224

How January really feels in União

Once humidity and wind are folded in, January averages 31 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
31
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in January is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

União weather by month

How January compares with the rest of the year at a glance. January is the 8th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan33° / 24°22821.812.22.6
Feb32° / 23°29622.212.22.7
Mar31° / 23°36327122.6
Apr31° / 23°32524.611.92.8
May32° / 23°14315.111.83.6
Jun33° / 23°234.611.74.2
Jul34° / 23°121.711.84.0
Aug35° / 24°20.511.93.2
Sep36° / 24°30.6122.3
Oct37° / 25°101.512.11.8
Nov36° / 25°354.512.22.0
Dec35° / 25°849.712.32.4

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 10% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 15% of January, with mostly cloudy or overcast conditions the remaining 75%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13466
23466
33268
43268
53070
62971
72872
82674
92674
102476
112476
122278
132278
142179
152080
162080
172080
182080
192080
202179
212278
222278
232377
242377
252377
262476
272476
282575
292476
302476
312575

Chance of precipitation in January

Any precipitation

União gets around 228 mm of rain over 21.8 wet days in January. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 70% and peaks near 75% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
155
257
359
461
562
664
765
866
968
1069
1170
1271
1372
1473
1574
1675
1775
1875
1975
2075
2175
2275
2375
2474
2574
2674
2773
2872
2972
3071
3170

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, January lands in the oppressive band about 78% of days. Sticky, muggy-or-worse air turns up on roughly 99% of them.

0%25%50%75%100%151015202531
Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1215749
2214759
31127710
41117810
51107910
61107910
7198010
8198010
9188011
10188011
11178111
12178111
13178111
14168112
15068212
16068113
17068113
18058114
19058015
20058015
21057916
22047917
23047818
24047818
25047719
26037720
27037621
28037621
29037522
30037522
31037423

Wind in January

Winds average 6 km/h in January.

Across January, daily wind ranges from about 6 km/h on the calmest days to 7 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (km/h)Feels
17calm
27calm
37calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm
316calm

Sunrise & sunset in January

DaylightNight

Daylight runs from about 12 h 18 min at the start of January to 12 h 12 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 6 minutes over January. Sunrise moves from 5:47 AM to 5:59 AM, and sunset from 6:02 PM to 6:11 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.35:476:02
212.35:476:03
312.35:486:03
412.35:486:04
512.35:496:04
612.35:496:04
712.35:506:05
812.35:506:05
912.35:516:06
1012.35:516:06
1112.25:516:06
1212.25:526:07
1312.25:526:07
1412.25:536:07
1512.25:536:08
1612.25:546:08
1712.25:546:08
1812.25:546:08
1912.25:556:09
2012.25:556:09
2112.25:566:09
2212.25:566:09
2312.25:566:10
2412.25:576:10
2512.25:576:10
2612.25:576:10
2712.25:586:10
2812.25:586:10
2912.25:586:11
3012.25:596:11
3112.25:596:11

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 5.13 kWh/m².

For context, solar energy here swings from a low near 4.76 kWh/m² to a high of 6.71 kWh/m² in October across the year — January's 5.13 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.4Bright
25.4Bright
35.3Bright
45.3Bright
55.3Bright
65.3Bright
75.2Bright
85.2Bright
95.2Bright
105.1Bright
115.1Bright
125.1Bright
135.1Bright
145.0Bright
155.0Bright
165.0Bright
175.0Bright
185.0Bright
195.0Bright
205.0Bright
215.0Bright
225.0Bright
235.0Bright
245.1Bright
255.1Bright
265.1Bright
275.1Bright
285.1Bright
295.1Bright
305.1Bright
315.1Bright
Planning a trip in January

Hazard calendar for União

In seasonPeak

In January, União sits inside its monsoon season. The full year is below, with each hazard's peak months called out.

União's monsoon runs January–April, when most of the year's rain falls.

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

Is January a good time to visit União?

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

2.6
Sightseeing
7th-best month of the year
4.5
Beach & pool
9th-best month of the year

January is a weaker month for outdoor sightseeing in União.

What to pack for União in January

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

In January, União sees daytime highs around 33°C and nights near 24°C. Pack light clothes and rain gear. Worth having: sun protection. About 22 days see rain.

light clothesrain gearsun protection

UV index in União in January

LowModerateHighVery highExtreme

Clear-sky midday UV in January 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 União peaks around March 14 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near July 24 at about 10 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highExtremeMar 14UV 15Jul 24UV 10
UV index (midday)Level
Jan13Extreme
Feb14Extreme
Mar15Extreme
Apr13Extreme
May11Extreme
Jun10Very high
Jul10Very high
Aug10Very high
Sep12Extreme
Oct12Extreme
Nov11Extreme
Dec11Extreme

Air quality in União in January

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in União is worst in November — around 22 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (June, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateNov 922 µg/m³Jun 1211 µg/m³
PM2.5 (µg/m³)Level
Jan15Moderate
Feb16Moderate
Mar14Moderate
Apr13Moderate
May12Good
Jun10Good
Jul14Moderate
Aug20Moderate
Sep17Moderate
Oct22Moderate
Nov22Moderate
Dec18Moderate
Location & terrain

Where is União?

União sits at 4.6°S, 42.9°W, 60 m above sea level, in Brazil. The nearest listed city is José de Freitas, 37 km away.

Topography around União

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

Within 3 km, the terrain around União has only modest variations in elevation — a maximum elevation change of 96 m around an average of 54 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 139 m; within 80 km, significant variations in elevation — a maximum elevation change of 318 m.

The land around União is covered by grassland (40%) and trees (24%) within 3 km, trees (58%) and grassland (23%) within 16 km, and trees (66%) within 80 km.

3 km
96 m
16 km
139 m
80 km
318 m
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
January weather nearby: José de Freitas 37 km · Coelho Neto 40 km · Miguel Alves 47 km · Teresina 56 km · Timon 57 km · Caxias 62 km · Altos 67 km · Aldeias Altas 67 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 União (-4.5858°, -42.8642°, elevation 60 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. 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).