Climate and average weather in Dumai
In Dumai, the weather is oppressive, hot, wet, and mostly cloudy and remarkably steady, with daytime highs holding near hot levels all year. The wettest stretch peaks around November.
Over the course of the year, the temperature in Dumai typically varies from 24°C to 32°C, and is rarely below 23°C or above 34°C. May is the hottest month of the year, while December is the coldest.
Based on the travel score, the best times of year to visit Dumai for warm-weather activities are from early January to early March and mid June to early August.
- Hottest
- May
- 32°
- Coldest
- Dec
- 24°
- Wettest
- Nov
- 387 mm
- Driest
- Feb
- 123 mm
- Rain / yr
- 2818 mm
- 293 wet days
- Daylight
- 11.9–12.1 h
- shortest–longest
- Elevation
- 7 m
- 1.7°N
- Clearest
- Feb
- 77% cloud
Dumai is city in Riau Province, Indonesia.
- Density
- 202/km²
- people per km²
- Founded
- 1999
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Dumai 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 January to early March.
Temperature through the year
Daily average highs and lows in Dumai, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
Temperatures in Dumai stay fairly even through the year, without a distinct hot or cool season. The warmest month is May, with an average high of 32°C and low of 25°C; the coolest is December, with an average low of 24°C and high of 31°C.
Days typically run about 7°C warmer than nights year-round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 31 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 31 | 31 | 31 |
| Avg low (°C) | 24 | 25 | 25 | 25 | 25 | 25 | 24 | 24 | 24 | 24 | 24 | 24 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| Jan | 31 | 24 |
| Feb | 32 | 25 |
| Mar | 32 | 25 |
| Apr | 32 | 25 |
| May | 32 | 25 |
| Jun | 32 | 25 |
| Jul | 32 | 24 |
| Aug | 32 | 24 |
| Sep | 32 | 24 |
| Oct | 31 | 24 |
| Nov | 31 | 24 |
| Dec | 31 | 24 |
How hot and cold Dumai 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, Dumai feels like about 41°C (around May 7). Nearly every day a year carries some heat stress, and 241 of them tip into dangerous heat (feels-like above 39°C), peaking in May.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels-like high (°C) | 37 | 38 | 40 | 41 | 41 | 41 | 40 | 40 | 40 | 39 | 39 | 37 |
| Air high (°C) | 31 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 31 | 31 | 31 |
| Feels-like low (°C) | 24 | 25 | 25 | 25 | 25 | 25 | 24 | 24 | 24 | 24 | 24 | 24 |
| Air low (°C) | 24 | 25 | 25 | 25 | 25 | 25 | 24 | 24 | 24 | 24 | 24 | 24 |
| Feels-like high (°C) | Air high (°C) | Feels-like low (°C) | Air low (°C) | |
|---|---|---|---|---|
| Jan | 37 | 31 | 24 | 24 |
| Feb | 38 | 32 | 25 | 25 |
| Mar | 40 | 32 | 25 | 25 |
| Apr | 41 | 32 | 25 | 25 |
| May | 41 | 32 | 25 | 25 |
| Jun | 41 | 32 | 25 | 25 |
| Jul | 40 | 32 | 24 | 24 |
| Aug | 40 | 32 | 24 | 24 |
| Sep | 40 | 32 | 24 | 24 |
| Oct | 39 | 31 | 24 | 24 |
| Nov | 39 | 31 | 24 | 24 |
| Dec | 37 | 31 | 24 | 24 |
Average hourly temperature in Dumai
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 May afternoons, near 32°C, and coldest before dawn in December, near 24°C.
Dumai 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 | 31° / 24° | 201 | 21.3 | 11.9 | 3.3 |
| Feb | 32° / 25° | 123 | 16.8 | 11.9 | 3.2 |
| Mar | 32° / 25° | 217 | 25.1 | 12 | 2.5 |
| Apr | 32° / 25° | 249 | 27.6 | 12 | 2.2 |
| May | 32° / 25° | 224 | 26.3 | 12.1 | 2.3 |
| Jun | 32° / 25° | 156 | 21.3 | 12.1 | 2.7 |
| Jul | 32° / 24° | 162 | 20.4 | 12.1 | 3.0 |
| Aug | 32° / 24° | 195 | 24 | 12.1 | 2.7 |
| Sep | 32° / 24° | 253 | 26.1 | 12 | 2.5 |
| Oct | 31° / 24° | 308 | 28.2 | 12 | 2.4 |
| Nov | 31° / 24° | 387 | 28.5 | 11.9 | 2.4 |
| Dec | 31° / 24° | 343 | 27.7 | 11.9 | 2.7 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
Dumai gets about 2818 mm of precipitation a year. On a typical day the chance of rain is very wet, but that rises and falls sharply with the seasons.
The wetter season lasts 4.4 months, from around Aug 18 to Dec 30, peaking in November at about 96% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Feb 10.
November is the wettest month by volume, with 387 mm over about 29 wet days; February is the driest, with 123 mm.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 69 | 62 | 81 | 92 | 85 | 71 | 66 | 78 | 87 | 91 | 95 | 89 |
| Rain days | 21 | 17 | 25 | 28 | 26 | 21 | 20 | 24 | 26 | 28 | 29 | 28 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 69 | 21 |
| Feb | 62 | 17 |
| Mar | 81 | 25 |
| Apr | 92 | 28 |
| May | 85 | 26 |
| Jun | 71 | 21 |
| Jul | 66 | 20 |
| Aug | 78 | 24 |
| Sep | 87 | 26 |
| Oct | 91 | 28 |
| Nov | 95 | 29 |
| Dec | 89 | 28 |
Monthly rainfall
Over a full year, Dumai collects about 2818 mm of rain across 293 wet days — roughly 235 mm in an average month.
It doesn’t fall evenly. November is the wettest month with 387 mm, while February is the driest at just 123 mm. The three wettest months alone bring about 37% of the year’s total.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (mm) | 201 | 123 | 217 | 249 | 224 | 156 | 162 | 195 | 253 | 308 | 387 | 343 |
| Rain days | 21 | 17 | 25 | 28 | 26 | 21 | 20 | 24 | 26 | 28 | 29 | 28 |
| Rainfall (mm) | Rain days | |
|---|---|---|
| Jan | 201 | 21 |
| Feb | 123 | 17 |
| Mar | 217 | 25 |
| Apr | 249 | 28 |
| May | 224 | 26 |
| Jun | 156 | 21 |
| Jul | 162 | 20 |
| Aug | 195 | 24 |
| Sep | 253 | 26 |
| Oct | 308 | 28 |
| Nov | 387 | 29 |
| Dec | 343 | 28 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In Dumai, the average share of the sky covered by clouds shows moderate seasonal variation over the course of the year.
The clearer part of the year begins around January 2 and lasts for 2.7 months, ending around March 25. The clearest month is February, when the sky is clear, mostly clear, or partly cloudy 21% of the time on average.
The cloudier part of the year begins around August 17 and lasts for 4.5 months, ending around January 1. The cloudiest month is November, when it is overcast or mostly cloudy 98% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 15 | 21 | 18 | 10 | 12 | 18 | 19 | 13 | 10 | 6 | 2 | 6 |
| Cloudier (%) | 85 | 79 | 82 | 90 | 88 | 82 | 81 | 87 | 90 | 94 | 98 | 94 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 15 | 85 |
| Feb | 21 | 79 |
| Mar | 18 | 82 |
| Apr | 10 | 90 |
| May | 12 | 88 |
| Jun | 18 | 82 |
| Jul | 19 | 81 |
| Aug | 13 | 87 |
| Sep | 10 | 90 |
| Oct | 6 | 94 |
| Nov | 2 | 98 |
| Dec | 6 | 94 |
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, Dumai barely changes through the year: days stay near 12 h 06 min of light in every season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 11.9 | 11.9 | 12.0 | 12.0 | 12.1 | 12.1 | 12.1 | 12.1 | 12.0 | 12.0 | 11.9 | 11.9 |
| Sunrise (AM) | 6:26 | 6:30 | 6:24 | 6:13 | 6:08 | 6:12 | 6:17 | 6:17 | 6:08 | 6:00 | 6:02 | 6:13 |
| Sunset (PM) | 6:21 | 6:27 | 6:24 | 6:16 | 6:13 | 6:17 | 6:22 | 6:20 | 6:09 | 5:58 | 5:57 | 6:08 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 11.9 | 6:26 | 6:21 |
| Feb | 11.9 | 6:30 | 6:27 |
| Mar | 12.0 | 6:24 | 6:24 |
| Apr | 12.0 | 6:13 | 6:16 |
| May | 12.1 | 6:08 | 6:13 |
| Jun | 12.1 | 6:12 | 6:17 |
| Jul | 12.1 | 6:17 | 6:22 |
| Aug | 12.1 | 6:17 | 6:20 |
| Sep | 12.0 | 6:08 | 6:09 |
| Oct | 12.0 | 6:00 | 5:58 |
| Nov | 11.9 | 6:02 | 5:57 |
| Dec | 11.9 | 6:13 | 6:08 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
Dumai averages about 1 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 0 and 3 days.
The sunnier stretch runs 3.0 months, from around Dec 28 to Mar 28. The sunniest month is February, with roughly 3 sunny days (gloomy).
The greyest month is November, down near 0 sunny days — about 98% fewer than the February peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 2 | 3 | 2 | 1 | 1 | 2 | 2 | 1 | 0 | 0 | 0 | 1 |
| Sky | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy |
| Sunny days | Sky | |
|---|---|---|
| Jan | 2 | Gloomy |
| Feb | 3 | Gloomy |
| Mar | 2 | Gloomy |
| Apr | 1 | Gloomy |
| May | 1 | Gloomy |
| Jun | 2 | Gloomy |
| Jul | 2 | Gloomy |
| Aug | 1 | Gloomy |
| Sep | 0 | Gloomy |
| Oct | 0 | Gloomy |
| Nov | 0 | Gloomy |
| Dec | 1 | 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.
Dumai 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 100% of the time. Even in January, the mildest month, the air is dry or comfortable only 0% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Muggy (%) | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Oppressive (%) | 39 | 43 | 19 | 1 | 1 | 4 | 11 | 11 | 8 | 7 | 7 | 19 |
| Miserable (%) | 60 | 56 | 81 | 99 | 99 | 96 | 89 | 89 | 92 | 93 | 93 | 81 |
| Muggy (%) | Oppressive (%) | Miserable (%) | |
|---|---|---|---|
| Jan | 1 | 39 | 60 |
| Feb | 1 | 43 | 56 |
| Mar | 1 | 19 | 81 |
| Apr | 0 | 1 | 99 |
| May | 0 | 1 | 99 |
| Jun | 0 | 4 | 96 |
| Jul | 0 | 11 | 89 |
| Aug | 0 | 11 | 89 |
| Sep | 0 | 8 | 92 |
| Oct | 0 | 7 | 93 |
| Nov | 0 | 7 | 93 |
| Dec | 0 | 19 | 81 |
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.
Wind in Dumai is steady company: average speeds sit near 6 km/h — calm — in every month of the year, with no meaningful windy or calm season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 6 | 6 | 6 | 5 | 5 | 5 | 6 | 5 | 5 | 5 | 5 | 6 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 6 | calm |
| Feb | 6 | calm |
| Mar | 6 | calm |
| Apr | 5 | calm |
| May | 5 | calm |
| Jun | 5 | calm |
| Jul | 6 | calm |
| Aug | 5 | calm |
| Sep | 5 | calm |
| Oct | 5 | calm |
| Nov | 5 | calm |
| Dec | 6 | calm |
Best time to visit Dumai
To characterize how pleasant the weather is in Dumai throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around late February, Dumai 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 times of year to visit Dumai for general outdoor tourist activities run from mid June to mid August and again from late December to early March, with a peak score in the first week of February.
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) | 3.2 | 3.2 | 2.5 | 2.2 | 2.3 | 2.7 | 3.0 | 2.7 | 2.5 | 2.4 | 2.4 | 2.7 |
| Rating | poor | poor | poor | poor | poor | poor | poor | poor | poor | poor | poor | poor |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 3.2 | poor |
| Feb | 3.2 | poor |
| Mar | 2.5 | poor |
| Apr | 2.2 | poor |
| May | 2.3 | poor |
| Jun | 2.7 | poor |
| Jul | 3.0 | poor |
| Aug | 2.7 | poor |
| Sep | 2.5 | poor |
| Oct | 2.4 | poor |
| Nov | 2.4 | poor |
| Dec | 2.7 | poor |
The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best times of year to visit Dumai for hot-weather activities run from early June to late August and again from late December to mid March, with a peak score in the second week of February.
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 Dumai, 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.
Dumai packs about the same all year — highs hold near 32°C. Across the year the things worth having are light clothes, rain gear and sun protection.
In May, Dumai sees daytime highs around 32°C and nights near 25°C. Pack light clothes and rain gear. Worth having: sun protection. About 26 days see rain.
Sea temperature near Dumai
Average ocean temperature at the nearest coast, month by month, banded into swim-comfort zones — the other half of the beach question.
The sea at the nearest coast (about 48 km away) is warmest in May at about 30°C and coldest in January near 29°C.
The water stays above 20°C all year — warm enough for a swim any month.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 29 | 29 | 29 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 29 | 29 |
| Comfort | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 29 | Tropical |
| Feb | 29 | Tropical |
| Mar | 29 | Tropical |
| Apr | 30 | Tropical |
| May | 30 | Tropical |
| Jun | 30 | Tropical |
| Jul | 30 | Tropical |
| Aug | 30 | Tropical |
| Sep | 30 | Tropical |
| Oct | 30 | Tropical |
| Nov | 29 | Tropical |
| Dec | 29 | Tropical |
UV index (midday) in Dumai 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 Dumai peaks around February 17 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 20 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 | 13 | 13 | 12 | 10 | 10 | 12 | 13 | 14 | 11 | 11 |
| Level | Extreme | Extreme | Extreme | Extreme | Extreme | Very high | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 13 | Extreme |
| Feb | 14 | Extreme |
| Mar | 13 | Extreme |
| Apr | 13 | Extreme |
| May | 12 | Extreme |
| Jun | 10 | Very high |
| Jul | 10 | Extreme |
| Aug | 12 | Extreme |
| Sep | 13 | Extreme |
| Oct | 14 | Extreme |
| Nov | 11 | Extreme |
| Dec | 11 | Extreme |
Average hourly UV index in Dumai
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 February the burn window is concentrated in the middle of the day: about 8 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 | 8 | 8 | 7.5 | 7.5 | 8 | 8 | 8 | 8 | 7.5 |
| UV ≥ 6 (h/day) | 6 | 6.5 | 6 | 6.5 | 6 | 5 | 5.5 | 6 | 6 | 6.5 | 5.5 | 5.5 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 8 | 6 |
| Feb | 8 | 6.5 |
| Mar | 8 | 6 |
| Apr | 8 | 6.5 |
| May | 8 | 6 |
| Jun | 7.5 | 5 |
| Jul | 7.5 | 5.5 |
| Aug | 8 | 6 |
| Sep | 8 | 6 |
| Oct | 8 | 6.5 |
| Nov | 8 | 5.5 |
| Dec | 7.5 | 5.5 |
Air quality in Dumai 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 Dumai is worst in September — around 43 µg/m³ PM2.5 (poor), about 2.9× the cleanest month (December, 15 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) | 18 | 31 | 36 | 26 | 20 | 21 | 37 | 42 | 43 | 30 | 15 | 15 |
| Level | Moderate | Moderate | Poor | Moderate | Moderate | Moderate | Poor | Poor | Poor | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 18 | Moderate |
| Feb | 31 | Moderate |
| Mar | 36 | Poor |
| Apr | 26 | Moderate |
| May | 20 | Moderate |
| Jun | 21 | Moderate |
| Jul | 37 | Poor |
| Aug | 42 | Poor |
| Sep | 43 | Poor |
| Oct | 30 | Moderate |
| Nov | 15 | Moderate |
| Dec | 15 | Moderate |
Growing season
Dumai 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. Dumai banks about 6,581 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around May.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Growing degree days (°C·days) | 543 | 505 | 569 | 556 | 578 | 553 | 561 | 557 | 536 | 553 | 528 | 540 |
| Growing degree days (°C·days) | |
|---|---|
| Jan | 543 |
| Feb | 505 |
| Mar | 569 |
| Apr | 556 |
| May | 578 |
| Jun | 553 |
| Jul | 561 |
| Aug | 557 |
| Sep | 536 |
| Oct | 553 |
| Nov | 528 |
| Dec | 540 |
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.
Dumai receives about 4.9 kWh/m² a day of solar energy — bright — and it stays remarkably steady, holding between 4.2 and 5.5 kWh/m² all year. For solar panels, output here is a flat line, not a seasonal wave.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 4.9 | 5.5 | 5.3 | 5.1 | 4.9 | 4.9 | 5.0 | 5.1 | 5.2 | 4.9 | 4.3 | 4.2 |
| Level | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 4.9 | Bright |
| Feb | 5.5 | Bright |
| Mar | 5.3 | Bright |
| Apr | 5.1 | Bright |
| May | 4.9 | Bright |
| Jun | 4.9 | Bright |
| Jul | 5.0 | Bright |
| Aug | 5.1 | Bright |
| Sep | 5.2 | Bright |
| Oct | 4.9 | Bright |
| Nov | 4.3 | Bright |
| Dec | 4.2 | Bright |
Where is Dumai?
Dumai sits at 1.7°N, 101.4°E, 7 m above sea level, in Indonesia. The nearest listed city is Balai Pungut, 70 km away.
Topography around Dumai
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Dumai.
Within 3 km, the terrain around Dumai has only modest variations in elevation — a maximum elevation change of 27 m around an average of 5 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 53 m; within 80 km, only modest variations in elevation — a maximum elevation change of 77 m.
The land around Dumai is covered by artificial surfaces (51%) and trees (31%) within 3 km, trees (66%) and water (20%) within 16 km, and trees (64%) and water (29%) within 80 km.
Indonesia travel facts
- Travel advisory
- Level 2
- Exercise Increased Caution
- Power plugs
- Type C / F
- 230 V · 50 Hz
- Prices
- ≈ 29% of US
- price level, 2025
- GDP per capita
- $5,060
- 2025
- Happiness
- 5.6 / 10
- World Happiness, 2025
- Safe drinking water
- 30%
- of population, 2024
- Homicide rate
- 0.3
- per 100k, 2022
- Road deaths
- 11.3
- per 100k/yr, 2019
- Income group
- Upper middle
- World Bank
- English
- Low
- EF EPI 471
- 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 Dumai (1.6671°, 101.4432°, elevation 7 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. 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).