Climate and average weather in Yei
In Yei, the summers are sweltering, fairly dry, and partly cloudy and the winters are warm and partly cloudy.
Over the course of the year, the temperature in Yei typically varies from 19°C to 34°C, and is rarely below 18°C or above 36°C. February is the hottest month of the year, while July is the coldest.
Based on the travel score, the best times of year to visit Yei for warm-weather activities are from mid June to mid July and mid November to late December.
- Hottest
- Feb
- 34°
- Coldest
- Jul
- 19°
- Wettest
- Oct
- 225 mm
- Driest
- Jan
- 10 mm
- Rain / yr
- 1465 mm
- 203 wet days
- Daylight
- 11.8–12.2 h
- shortest–longest
- Elevation
- 836 m
- 4.1°N
- Clearest
- Jan
- 53% cloud
Yei is City in South Sudan.
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Yei 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 mid November to late December.
Temperature through the year
Daily average highs and lows in Yei, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
Temperatures in Yei stay fairly even through the year, without a distinct hot or cool season. The warmest month is February, with an average high of 34°C and low of 22°C; the coolest is July, with an average low of 19°C and high of 27°C.
Days typically run about 9°C warmer than nights, with the widest day–night swing (around 11°C) in January.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 33 | 34 | 33 | 30 | 29 | 28 | 27 | 27 | 28 | 28 | 29 | 31 |
| Avg low (°C) | 21 | 22 | 22 | 21 | 20 | 19 | 19 | 19 | 19 | 19 | 20 | 20 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| Jan | 33 | 21 |
| Feb | 34 | 22 |
| Mar | 33 | 22 |
| Apr | 30 | 21 |
| May | 29 | 20 |
| Jun | 28 | 19 |
| Jul | 27 | 19 |
| Aug | 27 | 19 |
| Sep | 28 | 19 |
| Oct | 28 | 19 |
| Nov | 29 | 20 |
| Dec | 31 | 20 |
How hot and cold Yei 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, Yei feels like about 34°C (around February 7). About 102 days a year carry some heat stress, peaking in February.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels-like high (°C) | 32 | 34 | 33 | 32 | 31 | 29 | 29 | 29 | 29 | 30 | 30 | 31 |
| Air high (°C) | 33 | 34 | 33 | 30 | 29 | 28 | 27 | 27 | 28 | 28 | 29 | 31 |
| Feels-like low (°C) | 21 | 22 | 22 | 21 | 20 | 19 | 19 | 19 | 19 | 19 | 20 | 20 |
| Air low (°C) | 21 | 22 | 22 | 21 | 20 | 19 | 19 | 19 | 19 | 19 | 20 | 20 |
| Feels-like high (°C) | Air high (°C) | Feels-like low (°C) | Air low (°C) | |
|---|---|---|---|---|
| Jan | 32 | 33 | 21 | 21 |
| Feb | 34 | 34 | 22 | 22 |
| Mar | 33 | 33 | 22 | 22 |
| Apr | 32 | 30 | 21 | 21 |
| May | 31 | 29 | 20 | 20 |
| Jun | 29 | 28 | 19 | 19 |
| Jul | 29 | 27 | 19 | 19 |
| Aug | 29 | 27 | 19 | 19 |
| Sep | 29 | 28 | 19 | 19 |
| Oct | 30 | 28 | 19 | 19 |
| Nov | 30 | 29 | 20 | 20 |
| Dec | 31 | 31 | 20 | 20 |
Average hourly temperature in Yei
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 February afternoons, near 34°C, and coldest before dawn in July, near 19°C.
Yei 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° / 21° | 10 | 2 | 11.8 | 4.5 |
| Feb | 34° / 22° | 15 | 3.5 | 11.9 | 3.7 |
| Mar | 33° / 22° | 67 | 12.1 | 12 | 3.4 |
| Apr | 30° / 21° | 146 | 19.7 | 12.1 | 3.5 |
| May | 29° / 20° | 155 | 21.6 | 12.2 | 4.0 |
| Jun | 28° / 19° | 143 | 21.8 | 12.2 | 4.4 |
| Jul | 27° / 19° | 183 | 24.6 | 12.2 | 4.3 |
| Aug | 27° / 19° | 199 | 26.9 | 12.1 | 4.0 |
| Sep | 28° / 19° | 178 | 24.4 | 12 | 4.1 |
| Oct | 28° / 19° | 225 | 25.9 | 11.9 | 3.8 |
| Nov | 29° / 20° | 123 | 16 | 11.8 | 4.6 |
| Dec | 31° / 20° | 21 | 4 | 11.8 | 5.3 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
Yei gets about 1465 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 7.4 months, from around Apr 4 to Nov 14, peaking in August at about 88% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Jan 5.
October is the wettest month by volume, with 225 mm over about 26 wet days; January is the driest, with 10 mm.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 7 | 13 | 40 | 65 | 69 | 73 | 80 | 87 | 81 | 83 | 53 | 14 |
| Rain days | 2 | 4 | 12 | 20 | 22 | 22 | 25 | 27 | 24 | 26 | 16 | 4 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 7 | 2 |
| Feb | 13 | 4 |
| Mar | 40 | 12 |
| Apr | 65 | 20 |
| May | 69 | 22 |
| Jun | 73 | 22 |
| Jul | 80 | 25 |
| Aug | 87 | 27 |
| Sep | 81 | 24 |
| Oct | 83 | 26 |
| Nov | 53 | 16 |
| Dec | 14 | 4 |
Monthly rainfall
Over a full year, Yei collects about 1465 mm of rain across 203 wet days — roughly 122 mm in an average month.
It doesn’t fall evenly. October is the wettest month with 225 mm, while January is the driest at just 10 mm. The three wettest months alone bring about 41% of the year’s total.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (mm) | 10 | 15 | 67 | 146 | 155 | 143 | 183 | 199 | 178 | 225 | 123 | 21 |
| Rain days | 2 | 4 | 12 | 20 | 22 | 22 | 25 | 27 | 24 | 26 | 16 | 4 |
| Rainfall (mm) | Rain days | |
|---|---|---|
| Jan | 10 | 2 |
| Feb | 15 | 4 |
| Mar | 67 | 12 |
| Apr | 146 | 20 |
| May | 155 | 22 |
| Jun | 143 | 22 |
| Jul | 183 | 25 |
| Aug | 199 | 27 |
| Sep | 178 | 24 |
| Oct | 225 | 26 |
| Nov | 123 | 16 |
| Dec | 21 | 4 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In Yei, 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 November 18 and lasts for 3.8 months, ending around March 13. The clearest month is December, when the sky is clear, mostly clear, or partly cloudy 59% of the time on average.
The cloudier part of the year begins around June 3 and lasts for 5.5 months, ending around November 17. The cloudiest month is October, when it is overcast or mostly cloudy 74% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 59 | 54 | 38 | 27 | 34 | 37 | 35 | 33 | 36 | 26 | 39 | 59 |
| Cloudier (%) | 41 | 46 | 62 | 73 | 66 | 63 | 65 | 67 | 64 | 74 | 61 | 41 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 59 | 41 |
| Feb | 54 | 46 |
| Mar | 38 | 62 |
| Apr | 27 | 73 |
| May | 34 | 66 |
| Jun | 37 | 63 |
| Jul | 35 | 65 |
| Aug | 33 | 67 |
| Sep | 36 | 64 |
| Oct | 26 | 74 |
| Nov | 39 | 61 |
| Dec | 59 | 41 |
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, Yei barely changes through the year: days stay near 12 h 12 min of light in every season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 11.8 | 11.9 | 12.0 | 12.1 | 12.2 | 12.2 | 12.2 | 12.1 | 12.0 | 11.9 | 11.8 | 11.8 |
| Sunrise (AM) | 7:13 | 7:16 | 7:08 | 6:55 | 6:48 | 6:50 | 6:56 | 6:57 | 6:51 | 6:45 | 6:48 | 7:01 |
| Sunset (PM) | 7:00 | 7:08 | 7:06 | 7:00 | 6:59 | 7:05 | 7:09 | 7:05 | 6:52 | 6:40 | 6:37 | 6:46 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 11.8 | 7:13 | 7:00 |
| Feb | 11.9 | 7:16 | 7:08 |
| Mar | 12.0 | 7:08 | 7:06 |
| Apr | 12.1 | 6:55 | 7:00 |
| May | 12.2 | 6:48 | 6:59 |
| Jun | 12.2 | 6:50 | 7:05 |
| Jul | 12.2 | 6:56 | 7:09 |
| Aug | 12.1 | 6:57 | 7:05 |
| Sep | 12.0 | 6:51 | 6:52 |
| Oct | 11.9 | 6:45 | 6:40 |
| Nov | 11.8 | 6:48 | 6:37 |
| Dec | 11.8 | 7:01 | 6:46 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
Yei averages about 6 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 2 and 12 days.
The sunnier stretch runs 3.9 months, from around Nov 16 to Mar 13. The sunniest month is December, with roughly 11 sunny days (mixed).
The greyest month is July, down near 3 sunny days — about 76% fewer than the December peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 11 | 9 | 6 | 4 | 5 | 4 | 3 | 3 | 4 | 3 | 6 | 12 |
| Sky | Mixed | Mixed | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Gloomy | Mixed |
| Sunny days | Sky | |
|---|---|---|
| Jan | 11 | Mixed |
| Feb | 9 | Mixed |
| Mar | 6 | Gloomy |
| Apr | 4 | Gloomy |
| May | 5 | Gloomy |
| Jun | 4 | Gloomy |
| Jul | 3 | Gloomy |
| Aug | 3 | Gloomy |
| Sep | 4 | Gloomy |
| Oct | 3 | Gloomy |
| Nov | 6 | Gloomy |
| Dec | 12 | Mixed |
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.
In Yei, how humid it feels changes dramatically over the year.
The more humid part of the year lasts 8.3 months, from around March 21 to November 28. The muggiest month is April, when the air feels humid, muggy or worse about 97% of the time.
The most comfortable stretch runs from around November 29 to March 20, and January is the most comfortable month — the air is dry or comfortable 83% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 61 | 51 | 12 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 26 |
| Comfortable (%) | 22 | 24 | 17 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 6 | 28 |
| Humid (%) | 15 | 20 | 38 | 16 | 4 | 5 | 10 | 3 | 2 | 4 | 24 | 34 |
| Muggy (%) | 2 | 5 | 33 | 80 | 96 | 94 | 90 | 97 | 98 | 96 | 69 | 12 |
| Oppressive (%) | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | |
|---|---|---|---|---|---|
| Jan | 61 | 22 | 15 | 2 | 0 |
| Feb | 51 | 24 | 20 | 5 | 0 |
| Mar | 12 | 17 | 38 | 33 | 0 |
| Apr | 0 | 2 | 16 | 80 | 1 |
| May | 0 | 0 | 4 | 96 | 1 |
| Jun | 0 | 0 | 5 | 94 | 0 |
| Jul | 0 | 0 | 10 | 90 | 0 |
| Aug | 0 | 0 | 3 | 97 | 0 |
| Sep | 0 | 0 | 2 | 98 | 0 |
| Oct | 0 | 0 | 4 | 96 | 0 |
| Nov | 1 | 6 | 24 | 69 | 0 |
| Dec | 26 | 28 | 34 | 12 | 0 |
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 Yei is typically calm, near 7 km/h, and varies little with the seasons.
The windier part of the year lasts 5.3 months, from around Nov 25 to May 5. The windiest month is February, averaging about 9 km/h (calm).
The calmer part of the year runs from around May 6 to Nov 24, with July the calmest month at about 5 km/h.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 8 | 9 | 8 | 7 | 6 | 5 | 5 | 5 | 5 | 5 | 6 | 8 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 8 | calm |
| Feb | 9 | calm |
| Mar | 8 | calm |
| Apr | 7 | calm |
| May | 6 | calm |
| Jun | 5 | calm |
| Jul | 5 | calm |
| Aug | 5 | calm |
| Sep | 5 | calm |
| Oct | 5 | calm |
| Nov | 6 | calm |
| Dec | 8 | calm |
Hazard calendar for Yei
When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.
Yei's rainy season runs April–November, when most of the year's rain falls.
Best time to visit Yei
To characterize how pleasant the weather is in Yei throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around late December, Yei 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 Yei for general outdoor tourist activities run from mid June to mid July and again from mid November to late January, with a peak score in the second week of December.
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) | 4.5 | 3.7 | 3.4 | 3.5 | 4.0 | 4.4 | 4.3 | 4.0 | 4.1 | 3.9 | 4.6 | 5.3 |
| Rating | fair | fair | poor | fair | fair | fair | fair | fair | fair | fair | fair | fair |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 4.5 | fair |
| Feb | 3.7 | fair |
| Mar | 3.4 | poor |
| Apr | 3.5 | fair |
| May | 4.0 | fair |
| Jun | 4.4 | fair |
| Jul | 4.3 | fair |
| Aug | 4.0 | fair |
| Sep | 4.1 | fair |
| Oct | 3.9 | fair |
| Nov | 4.6 | fair |
| Dec | 5.3 | fair |
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 Yei for hot-weather activities is from late November to early March, with a peak score in the last week of December.
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 Yei, 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.
For a warm-season trip around February (highs near 34°C), the essentials are light clothes and sun protection. In the cold season around July (highs near 27°C), pack light clothes, rain gear and sun protection.
In February, Yei sees daytime highs around 34°C and nights near 22°C. Pack light clothes and sun protection. About 4 days see rain.
UV index (midday) in Yei 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 Yei peaks around March 17 at about 15 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 10 (extreme).
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) | 11 | 14 | 15 | 14 | 12 | 10 | 11 | 12 | 13 | 13 | 10 | 10 |
| Level | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Very high |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 11 | Extreme |
| Feb | 14 | Extreme |
| Mar | 15 | Extreme |
| Apr | 14 | Extreme |
| May | 12 | Extreme |
| Jun | 10 | Extreme |
| Jul | 11 | Extreme |
| Aug | 12 | Extreme |
| Sep | 13 | Extreme |
| Oct | 13 | Extreme |
| Nov | 10 | Extreme |
| Dec | 10 | Very high |
Average hourly UV index in Yei
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 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) | 7.5 | 8 | 8 | 8 | 8 | 7.5 | 7.5 | 8 | 8 | 8 | 7.5 | 7 |
| UV ≥ 6 (h/day) | 5.5 | 6.5 | 6.5 | 6.5 | 5.5 | 5.5 | 5.5 | 6 | 6 | 6 | 5.5 | 5 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 7.5 | 5.5 |
| Feb | 8 | 6.5 |
| Mar | 8 | 6.5 |
| Apr | 8 | 6.5 |
| May | 8 | 5.5 |
| Jun | 7.5 | 5.5 |
| Jul | 7.5 | 5.5 |
| Aug | 8 | 6 |
| Sep | 8 | 6 |
| Oct | 8 | 6 |
| Nov | 7.5 | 5.5 |
| Dec | 7 | 5 |
Air quality in Yei 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 Yei is worst in January — around 101 µg/m³ PM2.5 (unhealthy), about 7.6× the cleanest month (October, 13 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) | 101 | 55 | 27 | 15 | 14 | 21 | 22 | 17 | 14 | 13 | 18 | 49 |
| Level | Unhealthy | Poor | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Poor |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 101 | Unhealthy |
| Feb | 55 | Poor |
| Mar | 27 | Moderate |
| Apr | 15 | Moderate |
| May | 14 | Moderate |
| Jun | 21 | Moderate |
| Jul | 22 | Moderate |
| Aug | 17 | Moderate |
| Sep | 14 | Moderate |
| Oct | 13 | Moderate |
| Nov | 18 | Moderate |
| Dec | 49 | Poor |
Growing season
Yei 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. Yei banks about 5,439 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around February.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Growing degree days (°C·days) | 520 | 499 | 537 | 474 | 456 | 410 | 403 | 404 | 403 | 424 | 430 | 480 |
| Growing degree days (°C·days) | |
|---|---|
| Jan | 520 |
| Feb | 499 |
| Mar | 537 |
| Apr | 474 |
| May | 456 |
| Jun | 410 |
| Jul | 403 |
| Aug | 404 |
| Sep | 403 |
| Oct | 424 |
| Nov | 430 |
| Dec | 480 |
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.
Yei receives about 5.5 kWh/m² a day of solar energy — bright — and it stays remarkably steady, holding between 5.0 and 6.1 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) | 5.9 | 6.1 | 5.9 | 5.8 | 5.5 | 5.0 | 5.0 | 5.3 | 5.6 | 5.3 | 5.5 | 5.6 |
| Level | Bright | Intense | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 5.9 | Bright |
| Feb | 6.1 | Intense |
| Mar | 5.9 | Bright |
| Apr | 5.8 | Bright |
| May | 5.5 | Bright |
| Jun | 5.0 | Bright |
| Jul | 5.0 | Bright |
| Aug | 5.3 | Bright |
| Sep | 5.6 | Bright |
| Oct | 5.3 | Bright |
| Nov | 5.5 | Bright |
| Dec | 5.6 | Bright |
Where is Yei?
Yei sits at 4.1°N, 30.7°E, 836 m above sea level, in South Sudan. The nearest listed city is Koboko, 82 km away.
Topography around Yei
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Yei.
Within 3 km, the terrain around Yei has only modest variations in elevation — a maximum elevation change of 62 m around an average of 824 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 156 m; within 80 km, large variations in elevation — a maximum elevation change of 1,060 m.
The land around Yei is covered by shrubs (46%) and trees (21%) within 3 km, shrubs (51%) and grassland (34%) within 16 km, and shrubs (50%) and trees (34%) within 80 km.
South Sudan travel facts
- Travel advisory
- Level 4
- Do Not Travel
- Prices
- ≈ 6% of US
- price level, 2021
- GDP per capita
- $1,080
- 2015
- Happiness
- 2.8 / 10
- World Happiness, 2019
- Homicide rate
- 14
- per 100k, 2012
- Road deaths
- 36.7
- per 100k/yr, 2019
- Income group
- Low
- World Bank
- 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 Yei (4.0944°, 30.6764°, elevation 836 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).