Climate and average weather in União
In União, the weather is humid, sweltering, wet, and mostly clear and remarkably steady, with daytime highs holding near sweltering levels all year. The wettest stretch peaks around March.
Over the course of the year, the temperature in União typically varies from 23°C to 37°C, and is rarely below 22°C or above 39°C. October is the hottest month of the year, while April is the coldest.
Based on the travel score, the best time of year to visit União for warm-weather activities is from early May to mid August.
- Hottest
- Oct
- 37°
- Coldest
- Apr
- 23°
- Wettest
- Mar
- 363 mm
- Driest
- Aug
- 2 mm
- Rain / yr
- 1525 mm
- 134 wet days
- Daylight
- 11.7–12.3 h
- shortest–longest
- Elevation
- 60 m
- 4.6°S
- Clearest
- Sep
- 33% cloud
União is settlement in Uniao, Piaui, Brazil.
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
União weather by month, at a glance
The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.
Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around early May to mid August.
Temperature through the year
Daily average highs and lows in União, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
Temperatures in União stay fairly even through the year, without a distinct hot or cool season. The warmest month is October, with an average high of 37°C and low of 25°C; the coolest is April, with an average low of 23°C and high of 31°C.
Days typically run about 10°C warmer than nights, with the widest day–night swing (around 12°C) in October.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 33 | 32 | 31 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 36 | 35 |
| Avg low (°C) | 24 | 23 | 23 | 23 | 23 | 23 | 23 | 24 | 24 | 25 | 25 | 25 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| Jan | 33 | 24 |
| Feb | 32 | 23 |
| Mar | 31 | 23 |
| Apr | 31 | 23 |
| May | 32 | 23 |
| Jun | 33 | 23 |
| Jul | 34 | 23 |
| Aug | 35 | 24 |
| Sep | 36 | 24 |
| Oct | 37 | 25 |
| Nov | 36 | 25 |
| Dec | 35 | 25 |
How hot and cold União really feels
The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.
On the hottest afternoons, once humidity is folded in, União feels like about 40°C (around October 16). Nearly every day a year carries some heat stress, and 88 of them tip into dangerous heat (feels-like above 39°C), peaking in October.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels-like high (°C) | 37 | 37 | 37 | 38 | 38 | 36 | 36 | 37 | 39 | 40 | 40 | 39 |
| Air high (°C) | 33 | 32 | 31 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 36 | 35 |
| Feels-like low (°C) | 24 | 23 | 23 | 23 | 23 | 23 | 23 | 24 | 24 | 25 | 25 | 25 |
| Air low (°C) | 24 | 23 | 23 | 23 | 23 | 23 | 23 | 24 | 24 | 25 | 25 | 25 |
| Feels-like high (°C) | Air high (°C) | Feels-like low (°C) | Air low (°C) | |
|---|---|---|---|---|
| Jan | 37 | 33 | 24 | 24 |
| Feb | 37 | 32 | 23 | 23 |
| Mar | 37 | 31 | 23 | 23 |
| Apr | 38 | 31 | 23 | 23 |
| May | 38 | 32 | 23 | 23 |
| Jun | 36 | 33 | 23 | 23 |
| Jul | 36 | 34 | 23 | 23 |
| Aug | 37 | 35 | 24 | 24 |
| Sep | 39 | 36 | 24 | 24 |
| Oct | 40 | 37 | 25 | 25 |
| Nov | 40 | 36 | 25 | 25 |
| Dec | 39 | 35 | 25 | 25 |
Average hourly temperature in União
A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on October afternoons, near 37°C, and coldest before dawn in April, near 23°C.
União weather by month
Every month at a glance. Click a month for its detailed page.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 33° / 24° | 228 | 21.8 | 12.2 | 2.6 |
| Feb | 32° / 23° | 296 | 22.2 | 12.2 | 2.7 |
| Mar | 31° / 23° | 363 | 27 | 12 | 2.6 |
| Apr | 31° / 23° | 325 | 24.6 | 11.9 | 2.8 |
| May | 32° / 23° | 143 | 15.1 | 11.8 | 3.6 |
| Jun | 33° / 23° | 23 | 4.6 | 11.7 | 4.2 |
| Jul | 34° / 23° | 12 | 1.7 | 11.8 | 4.0 |
| Aug | 35° / 24° | 2 | 0.5 | 11.9 | 3.2 |
| Sep | 36° / 24° | 3 | 0.6 | 12 | 2.3 |
| Oct | 37° / 25° | 10 | 1.5 | 12.1 | 1.8 |
| Nov | 36° / 25° | 35 | 4.5 | 12.2 | 2.0 |
| Dec | 35° / 25° | 84 | 9.7 | 12.3 | 2.4 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
União gets about 1525 mm of precipitation a year. On a typical day the chance of rain is often wet, but that rises and falls sharply with the seasons.
The wetter season lasts 5.2 months, from around Dec 21 to May 26, peaking in March at about 90% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Aug 29.
March is the wettest month by volume, with 363 mm over about 27 wet days; August is the driest, with 2 mm.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 69 | 79 | 87 | 81 | 48 | 17 | 6 | 2 | 2 | 5 | 14 | 33 |
| Rain days | 22 | 22 | 27 | 25 | 15 | 5 | 2 | 1 | 1 | 2 | 5 | 10 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 69 | 22 |
| Feb | 79 | 22 |
| Mar | 87 | 27 |
| Apr | 81 | 25 |
| May | 48 | 15 |
| Jun | 17 | 5 |
| Jul | 6 | 2 |
| Aug | 2 | 1 |
| Sep | 2 | 1 |
| Oct | 5 | 2 |
| Nov | 14 | 5 |
| Dec | 33 | 10 |
Monthly rainfall
Over a full year, União collects about 1525 mm of rain across 134 wet days — roughly 127 mm in an average month.
It doesn’t fall evenly. March is the wettest month with 363 mm, while August is the driest at just 2 mm. The three wettest months alone bring about 65% of the year’s total.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (mm) | 228 | 296 | 363 | 325 | 143 | 23 | 12 | 2 | 3 | 10 | 35 | 84 |
| Rain days | 22 | 22 | 27 | 25 | 15 | 5 | 2 | 1 | 1 | 2 | 5 | 10 |
| Rainfall (mm) | Rain days | |
|---|---|---|
| Jan | 228 | 22 |
| Feb | 296 | 22 |
| Mar | 363 | 27 |
| Apr | 325 | 25 |
| May | 143 | 15 |
| Jun | 23 | 5 |
| Jul | 12 | 2 |
| Aug | 2 | 1 |
| Sep | 3 | 1 |
| Oct | 10 | 2 |
| Nov | 35 | 5 |
| Dec | 84 | 10 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In União, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.
The clearer part of the year begins around May 21 and lasts for 6.0 months, ending around November 19. The clearest month is September, when the sky is clear, mostly clear, or partly cloudy 90% of the time on average.
The cloudier part of the year begins around November 20 and lasts for 6.0 months, ending around May 20. The cloudiest month is March, when it is overcast or mostly cloudy 81% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 25 | 21 | 19 | 24 | 48 | 70 | 79 | 87 | 90 | 80 | 58 | 44 |
| Cloudier (%) | 75 | 79 | 81 | 76 | 52 | 30 | 21 | 13 | 10 | 20 | 42 | 56 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 25 | 75 |
| Feb | 21 | 79 |
| Mar | 19 | 81 |
| Apr | 24 | 76 |
| May | 48 | 52 |
| Jun | 70 | 30 |
| Jul | 79 | 21 |
| Aug | 87 | 13 |
| Sep | 90 | 10 |
| Oct | 80 | 20 |
| Nov | 58 | 42 |
| Dec | 44 | 56 |
Daylight, sunrise and sunset
Hours of daylight through the year, with sunrise and sunset times.
The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. Close to the equator, União barely changes through the year: days stay near 12 h 18 min of light in every season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 12.2 | 12.2 | 12.0 | 11.9 | 11.8 | 11.7 | 11.8 | 11.9 | 12.0 | 12.1 | 12.2 | 12.3 |
| Sunrise (AM) | 5:54 | 6:02 | 6:00 | 5:55 | 5:54 | 6:00 | 6:04 | 6:00 | 5:47 | 5:33 | 5:30 | 5:40 |
| Sunset (PM) | 6:08 | 6:11 | 6:02 | 5:49 | 5:41 | 5:44 | 5:50 | 5:51 | 5:45 | 5:40 | 5:43 | 5:56 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 12.2 | 5:54 | 6:08 |
| Feb | 12.2 | 6:02 | 6:11 |
| Mar | 12.0 | 6:00 | 6:02 |
| Apr | 11.9 | 5:55 | 5:49 |
| May | 11.8 | 5:54 | 5:41 |
| Jun | 11.7 | 6:00 | 5:44 |
| Jul | 11.8 | 6:04 | 5:50 |
| Aug | 11.9 | 6:00 | 5:51 |
| Sep | 12.0 | 5:47 | 5:45 |
| Oct | 12.1 | 5:33 | 5:40 |
| Nov | 12.2 | 5:30 | 5:43 |
| Dec | 12.3 | 5:40 | 5:56 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
União averages about 10 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 1 and 22 days.
The sunnier stretch runs 5.5 months, from around May 30 to Nov 12. The sunniest month is September, with roughly 22 sunny days (bright).
The greyest month is March, down near 2 sunny days — about 91% fewer than the September peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 3 | 3 | 2 | 2 | 7 | 12 | 16 | 21 | 22 | 18 | 10 | 7 |
| Sky | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Mixed | Bright | Bright | Bright | Bright | Mixed | Gloomy |
| Sunny days | Sky | |
|---|---|---|
| Jan | 3 | Gloomy |
| Feb | 3 | Gloomy |
| Mar | 2 | Gloomy |
| Apr | 2 | Gloomy |
| May | 7 | Gloomy |
| Jun | 12 | Mixed |
| Jul | 16 | Bright |
| Aug | 21 | Bright |
| Sep | 22 | Bright |
| Oct | 18 | Bright |
| Nov | 10 | Mixed |
| Dec | 7 | Gloomy |
Humidity comfort
Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.
Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.
União is humid all year round — on a typical day the air feels at least humid, and there is no real dry season to wait for.
The stickiest month is January, when it feels muggy, oppressive or miserable about 99% of the time. Even in August, the mildest month, the air is dry or comfortable only 5% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Comfortable (%) | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 5 | 2 | 1 | 0 | 0 |
| Humid (%) | 1 | 0 | 0 | 0 | 0 | 3 | 21 | 32 | 23 | 18 | 9 | 4 |
| Muggy (%) | 7 | 1 | 0 | 0 | 2 | 30 | 52 | 55 | 68 | 68 | 58 | 38 |
| Oppressive (%) | 78 | 70 | 55 | 40 | 55 | 62 | 24 | 8 | 7 | 13 | 32 | 55 |
| Miserable (%) | 14 | 29 | 45 | 60 | 42 | 5 | 0 | 0 | 0 | 0 | 0 | 4 |
| Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | Miserable (%) | |
|---|---|---|---|---|---|
| Jan | 0 | 1 | 7 | 78 | 14 |
| Feb | 0 | 0 | 1 | 70 | 29 |
| Mar | 0 | 0 | 0 | 55 | 45 |
| Apr | 0 | 0 | 0 | 40 | 60 |
| May | 0 | 0 | 2 | 55 | 42 |
| Jun | 0 | 3 | 30 | 62 | 5 |
| Jul | 2 | 21 | 52 | 24 | 0 |
| Aug | 5 | 32 | 55 | 8 | 0 |
| Sep | 2 | 23 | 68 | 7 | 0 |
| Oct | 1 | 18 | 68 | 13 | 0 |
| Nov | 0 | 9 | 58 | 32 | 0 |
| Dec | 0 | 4 | 38 | 55 | 4 |
Wind
Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.
This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.
Across the year, average wind speed in União is typically calm, near 7 km/h, and varies little with the seasons.
The windier part of the year lasts 6.5 months, from around Jun 10 to Dec 24. The windiest month is October, averaging about 9 km/h (calm).
The calmer part of the year runs from around Dec 25 to Jun 9, with April the calmest month at about 5 km/h.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 6 | 5 | 5 | 5 | 6 | 7 | 8 | 9 | 9 | 9 | 8 | 7 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 6 | calm |
| Feb | 5 | calm |
| Mar | 5 | calm |
| Apr | 5 | calm |
| May | 6 | calm |
| Jun | 7 | calm |
| Jul | 8 | calm |
| Aug | 9 | calm |
| Sep | 9 | calm |
| Oct | 9 | calm |
| Nov | 8 | calm |
| Dec | 7 | calm |
Hazard calendar for União
When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.
União's monsoon runs January–April, when most of the year's rain falls.
Best time to visit União
To characterize how pleasant the weather is in União throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around early August, União is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.
Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.
The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best time of year to visit União for general outdoor tourist activities is from early May to mid August, with a peak score in the second week of June.
The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Travel score (0–10) | 2.6 | 2.7 | 2.6 | 2.8 | 3.6 | 4.1 | 4.0 | 3.2 | 2.3 | 1.8 | 2.0 | 2.4 |
| Rating | poor | poor | poor | poor | fair | fair | fair | poor | poor | poor | poor | poor |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 2.6 | poor |
| Feb | 2.7 | poor |
| Mar | 2.6 | poor |
| Apr | 2.8 | poor |
| May | 3.6 | fair |
| Jun | 4.1 | fair |
| Jul | 4.0 | fair |
| Aug | 3.2 | poor |
| Sep | 2.3 | poor |
| Oct | 1.8 | poor |
| Nov | 2.0 | poor |
| Dec | 2.4 | poor |
The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit União for hot-weather activities is from late May to mid September, with a peak score in the last week of July.
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
What to pack for União, by month
Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.
União packs about the same all year — highs hold near 37°C. Across the year the things worth having are light clothes, sun protection and rain gear.
In October, União sees daytime highs around 37°C and nights near 25°C. Pack light clothes and sun protection.
UV index (midday) in União by month
Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.
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.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 13 | 14 | 15 | 13 | 11 | 10 | 10 | 10 | 12 | 12 | 11 | 11 |
| Level | Extreme | Extreme | Extreme | Extreme | Extreme | Very high | Very high | Very high | Extreme | Extreme | Extreme | Extreme |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 13 | Extreme |
| Feb | 14 | Extreme |
| Mar | 15 | Extreme |
| Apr | 13 | Extreme |
| May | 11 | Extreme |
| Jun | 10 | Very high |
| Jul | 10 | Very high |
| Aug | 10 | Very high |
| Sep | 12 | Extreme |
| Oct | 12 | Extreme |
| Nov | 11 | Extreme |
| Dec | 11 | Extreme |
Average hourly UV index in União
Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.
The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
UV falls off far faster than brightness as the sun drops, so even in March the burn window is concentrated in the middle of the day: about 8.5 hours a day reach index 3 (protection recommended), and 6.5 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV ≥ 3 (h/day) | 8 | 8 | 8.5 | 8 | 7.5 | 7 | 7.5 | 7.5 | 8 | 7.5 | 7.5 | 8 |
| UV ≥ 6 (h/day) | 6.5 | 6.5 | 6.5 | 6 | 5.5 | 5 | 5 | 5 | 6 | 5.5 | 5.5 | 5.5 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 8 | 6.5 |
| Feb | 8 | 6.5 |
| Mar | 8.5 | 6.5 |
| Apr | 8 | 6 |
| May | 7.5 | 5.5 |
| Jun | 7 | 5 |
| Jul | 7.5 | 5 |
| Aug | 7.5 | 5 |
| Sep | 8 | 6 |
| Oct | 7.5 | 5.5 |
| Nov | 7.5 | 5.5 |
| Dec | 8 | 5.5 |
Air quality in União by month
Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly 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).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 15 | 16 | 14 | 13 | 12 | 10 | 14 | 20 | 17 | 22 | 22 | 18 |
| Level | Moderate | Moderate | Moderate | Moderate | Good | Good | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 15 | Moderate |
| Feb | 16 | Moderate |
| Mar | 14 | Moderate |
| Apr | 13 | Moderate |
| May | 12 | Good |
| Jun | 10 | Good |
| Jul | 14 | Moderate |
| Aug | 20 | Moderate |
| Sep | 17 | Moderate |
| Oct | 22 | Moderate |
| Nov | 22 | Moderate |
| Dec | 18 | Moderate |
Growing season
União is frost-free year round — even the coldest nights rarely reach freezing, so there is no start or end to the growing season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Frost-free chance (%) | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Frost nights | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Frost-free chance (%) | Frost nights | |
|---|---|---|
| Jan | 100 | 0 |
| Feb | 100 | 0 |
| Mar | 100 | 0 |
| Apr | 100 | 0 |
| May | 100 | 0 |
| Jun | 100 | 0 |
| Jul | 100 | 0 |
| Aug | 100 | 0 |
| Sep | 100 | 0 |
| Oct | 100 | 0 |
| Nov | 100 | 0 |
| Dec | 100 | 0 |
Growing degree days
Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. União banks about 6,858 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around October.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Growing degree days (°C·days) | 563 | 490 | 535 | 516 | 544 | 538 | 569 | 597 | 610 | 652 | 624 | 618 |
| Growing degree days (°C·days) | |
|---|---|
| Jan | 563 |
| Feb | 490 |
| Mar | 535 |
| Apr | 516 |
| May | 544 |
| Jun | 538 |
| Jul | 569 |
| Aug | 597 |
| Sep | 610 |
| Oct | 652 |
| Nov | 624 |
| Dec | 618 |
Solar energy
Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.
Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.
União receives about 5.6 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 4.7 and 6.7 kWh/m².
The brighter stretch of the year lasts 5.1 months, from around Jul 23 to Dec 23. The brightest month is October, averaging about 6.7 kWh/m² (intense).
The dimmest month is April, down near 4.8 kWh/m² — roughly 29% less than the October peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 5.1 | 5.1 | 4.9 | 4.8 | 4.9 | 5.1 | 5.4 | 6.1 | 6.6 | 6.7 | 6.3 | 5.8 |
| Level | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Intense | Intense | Intense | Intense | Bright |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 5.1 | Bright |
| Feb | 5.1 | Bright |
| Mar | 4.9 | Bright |
| Apr | 4.8 | Bright |
| May | 4.9 | Bright |
| Jun | 5.1 | Bright |
| Jul | 5.4 | Bright |
| Aug | 6.1 | Intense |
| Sep | 6.6 | Intense |
| Oct | 6.7 | Intense |
| Nov | 6.3 | Intense |
| Dec | 5.8 | Bright |
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.
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
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).