Climate and average weather in As Sulayyil
In As Sulayyil, the summers are sweltering, dry, and mostly clear and the winters are warm and clear.
Over the course of the year, the temperature in As Sulayyil typically varies from 11°C to 43°C, and is rarely below 7°C or above 45°C. July is the hottest month of the year, while January is the coldest.
Based on the travel score, the best times of year to visit As Sulayyil for warm-weather activities are from early January to late February and mid November to late December.
- Hottest
- Jul
- 43°
- Coldest
- Jan
- 11°
- Wettest
- Apr
- 6 mm
- Driest
- Jun
- 0 mm
- Rain / yr
- 19 mm
- 4 wet days
- Daylight
- 10.8–13.2 h
- shortest–longest
- Elevation
- 606 m
- 20.5°N
- Clearest
- Oct
- 9% cloud
As Sulayyil is human settlement in Saudi Arabia.
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
As Sulayyil 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 late February.
Temperature through the year
Daily average highs and lows in As Sulayyil, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
The hot season lasts 4.8 months, from May 4 to September 26, with daily high temperatures above 38°C. The hottest month of the year in As Sulayyil is July, with an average high of 43°C and low of 30°C.
The cool season lasts 2.7 months, from November 28 to February 16, with daily high temperatures below 27°C. The coldest month of the year in As Sulayyil is January, with an average low of 11°C and high of 24°C.
Days typically run about 14°C warmer than nights year-round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 24 | 27 | 31 | 36 | 40 | 43 | 43 | 43 | 40 | 35 | 29 | 25 |
| Avg low (°C) | 11 | 14 | 18 | 23 | 26 | 28 | 30 | 29 | 26 | 21 | 16 | 12 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| Jan | 24 | 11 |
| Feb | 27 | 14 |
| Mar | 31 | 18 |
| Apr | 36 | 23 |
| May | 40 | 26 |
| Jun | 43 | 28 |
| Jul | 43 | 30 |
| Aug | 43 | 29 |
| Sep | 40 | 26 |
| Oct | 35 | 21 |
| Nov | 29 | 16 |
| Dec | 25 | 12 |
How hot and cold As Sulayyil 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, As Sulayyil feels like about 44°C (around July 14). About 226 days a year carry some heat stress, and 141 of them tip into dangerous heat (feels-like above 39°C), peaking in July.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels-like high (°C) | 24 | 27 | 31 | 36 | 40 | 43 | 43 | 43 | 40 | 35 | 29 | 25 |
| Air high (°C) | 24 | 27 | 31 | 36 | 40 | 43 | 43 | 43 | 40 | 35 | 29 | 25 |
| Feels-like low (°C) | 11 | 14 | 18 | 22 | 26 | 28 | 30 | 29 | 26 | 21 | 16 | 12 |
| Air low (°C) | 11 | 14 | 18 | 23 | 26 | 28 | 30 | 29 | 26 | 21 | 16 | 12 |
| Feels-like high (°C) | Air high (°C) | Feels-like low (°C) | Air low (°C) | |
|---|---|---|---|---|
| Jan | 24 | 24 | 11 | 11 |
| Feb | 27 | 27 | 14 | 14 |
| Mar | 31 | 31 | 18 | 18 |
| Apr | 36 | 36 | 22 | 23 |
| May | 40 | 40 | 26 | 26 |
| Jun | 43 | 43 | 28 | 28 |
| Jul | 43 | 43 | 30 | 30 |
| Aug | 43 | 43 | 29 | 29 |
| Sep | 40 | 40 | 26 | 26 |
| Oct | 35 | 35 | 21 | 21 |
| Nov | 29 | 29 | 16 | 16 |
| Dec | 25 | 25 | 12 | 12 |
Average hourly temperature in As Sulayyil
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 July afternoons, near 43°C, and coldest before dawn in January, near 11°C.
As Sulayyil 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 | 24° / 11° | 3 | 0.8 | 10.9 | 9.3 |
| Feb | 27° / 14° | 1 | 0.4 | 11.3 | 8.7 |
| Mar | 31° / 18° | 5 | 1.1 | 11.9 | 5.7 |
| Apr | 36° / 23° | 6 | 1.2 | 12.5 | 2.7 |
| May | 40° / 26° | 2 | 0.3 | 13 | 0.3 |
| Jun | 43° / 28° | 0 | 0 | 13.2 | 0.0 |
| Jul | 43° / 30° | 0 | 0 | 13.1 | 0.0 |
| Aug | 43° / 29° | 0 | 0 | 12.7 | 0.0 |
| Sep | 40° / 26° | 0 | 0 | 12.1 | 0.3 |
| Oct | 35° / 21° | 1 | 0.1 | 11.5 | 3.5 |
| Nov | 29° / 16° | 1 | 0.2 | 11 | 7.4 |
| Dec | 25° / 12° | 0 | 0.2 | 10.8 | 9.4 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
As Sulayyil gets about 19 mm of precipitation a year. On a typical day the chance of rain is mostly dry, and that barely changes with the seasons — rain is spread fairly evenly through the year.
April is the wettest month by volume, with 6 mm over about 1 wet days; June is the driest, with 0 mm.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 3 | 2 | 4 | 4 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
| Rain days | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 3 | 1 |
| Feb | 2 | 0 |
| Mar | 4 | 1 |
| Apr | 4 | 1 |
| May | 1 | 0 |
| Jun | 0 | 0 |
| Jul | 0 | 0 |
| Aug | 0 | 0 |
| Sep | 0 | 0 |
| Oct | 0 | 0 |
| Nov | 1 | 0 |
| Dec | 1 | 0 |
Monthly rainfall
Over a full year, As Sulayyil collects about 19 mm of rain across 4 wet days — roughly 2 mm in an average month.
It doesn’t fall evenly. April is the wettest month with 6 mm, while June is the driest at just 0 mm. The three wettest months alone bring about 72% of the year’s total.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (mm) | 3 | 1 | 5 | 6 | 2 | 0 | 0 | 0 | 0 | 1 | 1 | 0 |
| Rain days | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Rainfall (mm) | Rain days | |
|---|---|---|
| Jan | 3 | 1 |
| Feb | 1 | 0 |
| Mar | 5 | 1 |
| Apr | 6 | 1 |
| May | 2 | 0 |
| Jun | 0 | 0 |
| Jul | 0 | 0 |
| Aug | 0 | 0 |
| Sep | 0 | 0 |
| Oct | 1 | 0 |
| Nov | 1 | 0 |
| Dec | 0 | 0 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In As Sulayyil, 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 August 29 and lasts for 4.1 months, ending around December 31. The clearest month is September, when the sky is clear, mostly clear, or partly cloudy 96% of the time on average.
The cloudier part of the year begins around June 18 and lasts for 2.4 months, ending around August 28. The cloudiest month is July, when it is overcast or mostly cloudy 19% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 89 | 93 | 90 | 89 | 93 | 91 | 81 | 85 | 96 | 96 | 94 | 92 |
| Cloudier (%) | 11 | 7 | 10 | 11 | 7 | 9 | 19 | 15 | 4 | 4 | 6 | 8 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 89 | 11 |
| Feb | 93 | 7 |
| Mar | 90 | 10 |
| Apr | 89 | 11 |
| May | 93 | 7 |
| Jun | 91 | 9 |
| Jul | 81 | 19 |
| Aug | 85 | 15 |
| Sep | 96 | 4 |
| Oct | 96 | 4 |
| Nov | 94 | 6 |
| Dec | 92 | 8 |
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. The longest day, around June 2, brings about 13 h 12 min of light; the shortest, around January 1, only 10 h 48 min — a swing of roughly 2 h 24 min.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 10.9 | 11.3 | 11.9 | 12.5 | 13.0 | 13.2 | 13.1 | 12.7 | 12.1 | 11.5 | 11.0 | 10.8 |
| Sunrise (AM) | 6:40 | 6:33 | 6:12 | 5:44 | 5:25 | 5:21 | 5:29 | 5:41 | 5:49 | 5:57 | 6:13 | 6:31 |
| Sunset (PM) | 5:34 | 5:51 | 6:03 | 6:12 | 6:23 | 6:35 | 6:37 | 6:23 | 5:55 | 5:28 | 5:13 | 5:17 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 10.9 | 6:40 | 5:34 |
| Feb | 11.3 | 6:33 | 5:51 |
| Mar | 11.9 | 6:12 | 6:03 |
| Apr | 12.5 | 5:44 | 6:12 |
| May | 13.0 | 5:25 | 6:23 |
| Jun | 13.2 | 5:21 | 6:35 |
| Jul | 13.1 | 5:29 | 6:37 |
| Aug | 12.7 | 5:41 | 6:23 |
| Sep | 12.1 | 5:49 | 5:55 |
| Oct | 11.5 | 5:57 | 5:28 |
| Nov | 11.0 | 6:13 | 5:13 |
| Dec | 10.8 | 6:31 | 5:17 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
As Sulayyil averages about 25 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 18 and 29 days.
The sunnier stretch runs 4.1 months, from around Sep 1 to Jan 2. The sunniest month is September, with roughly 27 sunny days (brilliant).
The greyest month is July, down near 19 sunny days — about 30% fewer than the September peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 25 | 24 | 26 | 24 | 27 | 24 | 19 | 21 | 27 | 29 | 27 | 26 |
| Sky | Brilliant | Brilliant | Brilliant | Brilliant | Brilliant | Brilliant | Bright | Bright | Brilliant | Brilliant | Brilliant | Brilliant |
| Sunny days | Sky | |
|---|---|---|
| Jan | 25 | Brilliant |
| Feb | 24 | Brilliant |
| Mar | 26 | Brilliant |
| Apr | 24 | Brilliant |
| May | 27 | Brilliant |
| Jun | 24 | Brilliant |
| Jul | 19 | Bright |
| Aug | 21 | Bright |
| Sep | 27 | Brilliant |
| Oct | 29 | Brilliant |
| Nov | 27 | Brilliant |
| Dec | 26 | Brilliant |
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 As Sulayyil, the air stays dry or comfortable essentially all year. Even in April, the muggiest month, it feels humid or worse only about 3% of the time — humidity is not something you need to plan around here.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 99 | 99 | 95 | 91 | 96 | 99 | 98 | 98 | 99 | 97 | 95 | 97 |
| Comfortable (%) | 1 | 1 | 4 | 6 | 3 | 1 | 2 | 1 | 0 | 2 | 5 | 3 |
| Humid (%) | 0 | 0 | 2 | 2 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 0 |
| Muggy (%) | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | |
|---|---|---|---|---|
| Jan | 99 | 1 | 0 | 0 |
| Feb | 99 | 1 | 0 | 0 |
| Mar | 95 | 4 | 2 | 0 |
| Apr | 91 | 6 | 2 | 1 |
| May | 96 | 3 | 0 | 1 |
| Jun | 99 | 1 | 0 | 0 |
| Jul | 98 | 2 | 1 | 0 |
| Aug | 98 | 1 | 1 | 0 |
| Sep | 99 | 0 | 0 | 0 |
| Oct | 97 | 2 | 1 | 1 |
| Nov | 95 | 5 | 0 | 0 |
| Dec | 97 | 3 | 0 | 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 As Sulayyil is typically light breeze, near 13 km/h, and varies little with the seasons.
The windier part of the year lasts 4.1 months, from around Jan 6 to May 11. The windiest month is March, averaging about 15 km/h (light breeze).
The calmer part of the year runs from around Aug 9 to Nov 20, with September the calmest month at about 10 km/h.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 13 | 14 | 15 | 14 | 12 | 12 | 14 | 12 | 10 | 10 | 12 | 12 |
| Feels | light breeze | light breeze | light breeze | light breeze | light breeze | calm | light breeze | calm | calm | calm | light breeze | light breeze |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 13 | light breeze |
| Feb | 14 | light breeze |
| Mar | 15 | light breeze |
| Apr | 14 | light breeze |
| May | 12 | light breeze |
| Jun | 12 | calm |
| Jul | 14 | light breeze |
| Aug | 12 | calm |
| Sep | 10 | calm |
| Oct | 10 | calm |
| Nov | 12 | light breeze |
| Dec | 12 | light breeze |
Hazard calendar for As Sulayyil
When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.
As Sulayyil sees seasonal dust haze (January–September), heaviest in July.
Best time to visit As Sulayyil
To characterize how pleasant the weather is in As Sulayyil throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around mid February, As Sulayyil 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 As Sulayyil for general outdoor tourist activities is from mid November to late February, with a peak score in the last 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) | 9.3 | 8.6 | 5.7 | 2.7 | 0.3 | 0.0 | 0.0 | 0.0 | 0.4 | 3.5 | 7.3 | 9.3 |
| Rating | ideal | ideal | good | poor | poor | poor | poor | poor | poor | fair | good | ideal |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 9.3 | ideal |
| Feb | 8.6 | ideal |
| Mar | 5.7 | good |
| Apr | 2.7 | poor |
| May | 0.3 | poor |
| Jun | 0.0 | poor |
| Jul | 0.0 | poor |
| Aug | 0.0 | poor |
| Sep | 0.4 | poor |
| Oct | 3.5 | fair |
| Nov | 7.3 | good |
| Dec | 9.3 | ideal |
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 As Sulayyil for hot-weather activities run from late January to early April and again from mid October to early January, with a peak score in the third week of November.
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 As Sulayyil, 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 July (highs near 43°C), the essentials are light clothes and sun protection. In the cold season around January (highs near 24°C), pack light clothes and sun protection.
In July, As Sulayyil sees daytime highs around 43°C and nights near 30°C. Pack light clothes and sun protection.
UV index (midday) in As Sulayyil 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 As Sulayyil peaks around April 14 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 5 (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) | 8 | 9 | 11 | 12 | 10 | 12 | 10 | 11 | 7 | 10 | 7 | 5 |
| Level | Very high | Very high | Extreme | Extreme | Very high | Extreme | Extreme | Extreme | Very high | Very high | High | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 8 | Very high |
| Feb | 9 | Very high |
| Mar | 11 | Extreme |
| Apr | 12 | Extreme |
| May | 10 | Very high |
| Jun | 12 | Extreme |
| Jul | 10 | Extreme |
| Aug | 11 | Extreme |
| Sep | 7 | Very high |
| Oct | 10 | Very high |
| Nov | 7 | High |
| Dec | 5 | Moderate |
Average hourly UV index in As Sulayyil
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 April the burn window is concentrated in the middle of the day: about 8 hours a day reach index 3 (protection recommended), and 6 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) | 6 | 7 | 7.5 | 8 | 8 | 8.5 | 8 | 8 | 6.5 | 7 | 6 | 5 |
| UV ≥ 6 (h/day) | 3.5 | 4.5 | 5.5 | 6 | 5.5 | 6 | 5.5 | 6 | 3.5 | 4.5 | 3 | 0 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 6 | 3.5 |
| Feb | 7 | 4.5 |
| Mar | 7.5 | 5.5 |
| Apr | 8 | 6 |
| May | 8 | 5.5 |
| Jun | 8.5 | 6 |
| Jul | 8 | 5.5 |
| Aug | 8 | 6 |
| Sep | 6.5 | 3.5 |
| Oct | 7 | 4.5 |
| Nov | 6 | 3 |
| Dec | 5 | 0 |
Air quality in As Sulayyil 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 As Sulayyil is worst in March — around 110 µg/m³ PM2.5 (unhealthy), about 2.7× the cleanest month (October, 41 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) | 77 | 94 | 110 | 101 | 82 | 64 | 77 | 69 | 47 | 41 | 57 | 65 |
| Level | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Poor | Poor | Unhealthy | Unhealthy |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 77 | Unhealthy |
| Feb | 94 | Unhealthy |
| Mar | 110 | Unhealthy |
| Apr | 101 | Unhealthy |
| May | 82 | Unhealthy |
| Jun | 64 | Unhealthy |
| Jul | 77 | Unhealthy |
| Aug | 69 | Unhealthy |
| Sep | 47 | Poor |
| Oct | 41 | Poor |
| Nov | 57 | Unhealthy |
| Dec | 65 | Unhealthy |
Growing season
As Sulayyil 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. As Sulayyil banks about 6,548 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around July.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Growing degree days (°C·days) | 229 | 290 | 455 | 575 | 721 | 756 | 823 | 814 | 688 | 551 | 380 | 266 |
| Growing degree days (°C·days) | |
|---|---|
| Jan | 229 |
| Feb | 290 |
| Mar | 455 |
| Apr | 575 |
| May | 721 |
| Jun | 756 |
| Jul | 823 |
| Aug | 814 |
| Sep | 688 |
| Oct | 551 |
| Nov | 380 |
| Dec | 266 |
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.
As Sulayyil receives about 6.4 kWh/m² a day of solar energy on average — intense — with a clear seasonal swing between 4.9 and 7.7 kWh/m².
The brighter stretch of the year lasts 6.9 months, from around Mar 9 to Oct 3. The brightest month is May, averaging about 7.6 kWh/m² (intense).
The dimmest month is January, down near 5.0 kWh/m² — roughly 34% less than the May peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 5.0 | 5.8 | 6.6 | 7.3 | 7.7 | 7.4 | 7.2 | 7.0 | 6.7 | 6.2 | 5.4 | 5.0 |
| Level | Bright | Bright | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Intense | Bright | Bright |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 5.0 | Bright |
| Feb | 5.8 | Bright |
| Mar | 6.6 | Intense |
| Apr | 7.3 | Intense |
| May | 7.7 | Intense |
| Jun | 7.4 | Intense |
| Jul | 7.2 | Intense |
| Aug | 7.0 | Intense |
| Sep | 6.7 | Intense |
| Oct | 6.2 | Intense |
| Nov | 5.4 | Bright |
| Dec | 5.0 | Bright |
Where is As Sulayyil?
As Sulayyil sits at 20.5°N, 45.6°E, 606 m above sea level, in Saudi Arabia. The nearest listed city is Laylá, 236 km away.
Topography around As Sulayyil
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of As Sulayyil.
Within 3 km, the terrain around As Sulayyil has only modest variations in elevation — a maximum elevation change of 40 m around an average of 606 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 123 m; within 80 km, significant variations in elevation — a maximum elevation change of 428 m.
The land around As Sulayyil is covered by bare terrain (67%) and artificial surfaces (25%) within 3 km, bare terrain (94%) within 16 km, and bare terrain (97%) within 80 km.
Saudi Arabia travel facts
- Travel advisory
- Level 3
- Reconsider Travel
- Power plugs
- Type G
- 230 V · 60 Hz
- Prices
- ≈ 47% of US
- price level, 2025
- GDP per capita
- $34,537
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Homicide rate
- 0.9
- per 100k, 2019
- Road deaths
- 35.9
- per 100k/yr, 2019
- Income group
- High
- World Bank
- English
- Very low
- EF EPI 404
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 As Sulayyil (20.4607°, 45.5779°, elevation 606 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).