Solarposition.org

Surat Thani · Thailand · 9.54° N · 99.94° E

Solar position in Ko Samui

Sun position, daylight and the best solar panel angle for Ko Samui — computed for 9.54° N, 99.94° E, 8 m above sea level.

Sunrise today06:09102° ESE
Sunset today17:59258° WSW
Best panel angle9°year-round, facing south
Off-grid angle20°best for the darkest month

The sun right now

Azimuth180.0°
Elevation68.7°
At solar noon, 12:04Open on the sun map

Sun in Ko Samui today

Saturday, 24 October 2026 · local time UTC+7

EventTimeDirection / height
Astronomical dawn04:58sun 18° below horizon
Nautical dawn05:2212° below
Civil dawn05:476° below
Sunrise06:09102° ESE
Golden hour ends06:37sun 6° up
Solar noon12:0468.7° high
Golden hour starts17:31sun 6° up
Sunset17:59258° WSW
Civil dusk18:216° below
Nautical dusk18:4512° below
Astronomical dusk19:1018° below
Day length11 h 51 min

Sun path diagram for Ko Samui

Where the sun stands in the sky: the centre is straight overhead, the outer ring is the horizon. Numbers mark local clock hours.

15°30°45°60°75°N30°60°E120°150°S210°240°W300°330°June solstice789101112131415161718EquinoxDecember solstice7891011121314151617Today
  • June solstice
  • Equinox
  • December solstice
  • Today

On the June solstice the sun reaches 76.1° at solar noon in Ko Samui; on the December solstice only 57.0°. Sunrise swings from 66° ENE in June to 114° ESE in December — a 48° arc along the horizon.

Sunrise, sunset and sun height by month

Values for the 21st of each month, local clock time including daylight saving time.

MonthSunriseSolar noonSunsetDay lengthNoon elevation
January06:4112:3118:2111 h 39 min60.6°
February06:3712:3318:3011 h 52 min69.9°
March06:2412:2718:3112 h 07 min80.7°
April06:0712:1818:3012 h 23 min87.7°
May05:5912:1618:3412 h 36 min79.3°
June06:0112:2218:4212 h 41 min76.1°
July06:0812:2618:4412 h 36 min79.1°
August06:1112:2318:3512 h 23 min87.4°
September06:0912:1318:1712 h 07 min81.2°
October06:0812:0418:0011 h 52 min69.8°
November06:1612:0517:5511 h 39 min60.6°
December06:3112:1818:0511 h 34 min57.0°

A year of daylight in Ko Samui

Each column is one day of 2026. Bright: sun above the horizon; soft: civil twilight; line: solar noon. Steps are daylight saving time changes.

00:0003:0006:0009:0012:0015:0018:0021:0000:00JanFebMarAprMayJunJulAugSepOctNovDec

Best solar panel angle in Ko Samui

Fixed array facing south (azimuth 180°). Energy per kWp from NASA POWER monthly climate, including clouds, temperature and snow reflection.

9°collects the most energy over a year: 1448 kWh per kWp.

20°gives the most in the darkest month — the one an off-grid system is sized for.

30%40%50%60%70%80%90%100%0°10°20°30°40°50°60°70°80°90°Best year-round 9°Best worst-month 20°70°Yearly energyWorst-month energy
  • Yearly energy
  • Worst-month energy
TiltkWh/kWp per yearShare of best yearDecember kWh/kWp/dayBest ÷ worst month
0°143599%3.131.5×
9° year-round best1448100%3.351.4×
10° = latitude1447100%3.371.4×
15°1441100%3.461.4×
20° off-grid best142698%3.531.4×
30°137095%3.601.5×
45°122785%3.551.8×
60°102371%3.302.3×
70°86560%3.042.7×
90°59041%2.312.5×

A fixed array in Ko Samui produces the most over a year at 9°. The design month for an off-grid system is December: at 20° it makes 3.53 kWh per kWp a day, 5% more than at 9°, and costs 2% of the yearly total. Why steep panels win winter.

Off-grid solar in Ko Samui at 70°

Daily energy of 1 kWp by month. Bars: panels at 70°. Line: panels at 9° (year-round best).

0123456January: 3.55 (70°)3.5JanFebruary: 3.58 (70°)3.6FebMarch: 2.91 (70°)2.9MarApril: 1.99 (70°)2.0AprMay: 1.49 (70°)1.5MayJune: 1.31 (70°)1.3JunJuly: 1.37 (70°)1.4JulAugust: 1.69 (70°)1.7AugSeptember: 2.24 (70°)2.2SepOctober: 2.55 (70°)2.6OctNovember: 2.80 (70°)2.8NovDecember: 3.04 (70°)3.0Dec9°
MonthSun hours, flatSun hours at 70°kWh/kWp/day at 70°at 9°Mean temp.
January4.674.353.553.9526.7 °C
February5.594.403.584.6427.1 °C
March5.963.602.914.7828.1 °C
April5.862.511.994.5429.2 °C
May5.311.901.494.0329.0 °C
June5.041.681.313.7928.3 °C
July4.961.751.373.7627.9 °C
August5.052.141.693.9027.8 °C
September4.992.792.243.9527.6 °C
October4.473.172.553.6227.6 °C
November4.053.462.803.3527.6 °C
December3.983.743.043.3527.0 °C
Year4.99 avg2.95 avg865 kWh1448 kWh

Sizing example. To run a 1 kWh-per-day load through June on LiFePO4 batteries (charge controller, battery and inverter losses included) you need about 900 Wp of panels at 70°, versus 350 Wp at 9°. Here the lower tilt is the better winter choice — the sun stays high enough. Size your own system.

Row spacing in Ko Samui

Distance between rows of 2 m long panels (slope length) so that no row shades the next between 10:00 and 14:00 solar time on the winter solstice.

2.1 mrow pitch at 70°

2.2 mrow pitch at 9°

Row spacing calculator

How Ko Samui compares in Thailand

Against the other 294 places in Thailand with climate data, for a fixed array at its best angle.

227thof 295 places in Thailand for sunshine, shared: 4.99 peak sun hours a day on flat ground.

−4%solar energy a year compared with the average place in Thailand: 1,448 against 1,509 kWh per kWp.

−15 mindaylight on the longest day, compared with Bangkok: 12 h 41 min against 12 h 56 min.

9°best year-round tilt here; across Thailand it runs from 4° in Narathiwat to 23° in Mae Chan.

Of the 295 places in Thailand, Bangkok and 7 other places get the most sun (5.23 peak sun hours a day) and Mae Ramat the least (4.74); Ko Samui ranks joint 227th. In its darkest month, June, 1 kWp of off-grid panels at 70° makes 1.31 kWh a day here, against 1.53 kWh on average in Thailand. The shortest day lasts 11 h 34 min, +15 min compared with Bangkok.

The sunniest places in Thailand

Solar forecast for Ko Samui, next 48 hours

Expected output of 1 kWp at 70°, computed from the ICON-EU weather model of the Deutscher Wetterdienst (DWD), Europe.

Loading the latest forecast…

Questions about the sun in Ko Samui

What is the best solar panel angle in Ko Samui?
For a fixed array facing south, the best year-round tilt in Ko Samui is 9°, worth about 1448 kWh per kWp a year. An off-grid system that has to get through December does better at about 20°.
What time is sunrise and sunset in Ko Samui today?
On 24 October 2026 the sun rises at 06:09 and sets at 17:59 local time (UTC+7), giving 11 h 51 min of daylight. Solar noon is at 12:04.
How many peak sun hours does Ko Samui get?
On a flat surface 5.0 hours a day averaged over the year, from 4.0 in December to 6.0 in March. Panels tilted at 70° receive 1.7 sun hours a day in June.
How high does the sun get in Ko Samui?
At solar noon the sun stands 76.1° above the horizon on the June solstice and 57.0° on the December solstice.
Is Ko Samui a good place for solar panels?
With 5.0 peak sun hours a day on flat ground, Ko Samui ranks joint 227th of 295 places in Thailand for sunshine. A 1 kWp array at the best angle (9°) makes about 1,448 kWh a year here, 4% less than the average place in Thailand.

Places near Ko Samui

All places in Thailand

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Sun positions: NREL Solar Position Algorithm. Climate: NASA POWER monthly climatology (NASA Langley Research Center). Forecast: Deutscher Wetterdienst, ICON-EU (CC BY 4.0), processed. Places: GeoNames (CC BY 4.0). Time zones: IANA. Sources and licences.