Solarposition.org

Hanoi · Vietnam · 21.12° N · 105.87° E

Solar position in Cổ Lóa

Sun position, daylight and the best solar panel angle for Cổ Lóa — computed for 21.12° N, 105.87° E, 17 m above sea level.

Sunrise today05:55103° ESE
Sunset today17:25257° WSW
Best panel angle16°year-round, facing south
Off-grid angle38°best for the darkest month

The sun right now

Azimuth180.0°
Elevation56.8°
At solar noon, 11:40Open on the sun map

Sun in Cổ Lóa today

Sunday, 25 October 2026 · local time UTC+7

EventTimeDirection / height
Astronomical dawn04:41sun 18° below horizon
Nautical dawn05:0712° below
Civil dawn05:336° below
Sunrise05:55103° ESE
Golden hour ends06:26sun 6° up
Solar noon11:4056.8° high
Golden hour starts16:54sun 6° up
Sunset17:25257° WSW
Civil dusk17:476° below
Nautical dusk18:1312° below
Astronomical dusk18:3918° below
Day length11 h 29 min

Sun path diagram for Cổ Lóa

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 solstice6789101112131415161718EquinoxDecember solstice7891011121314151617Today
  • June solstice
  • Equinox
  • December solstice
  • Today

On the June solstice the sun reaches 87.7° at solar noon in Cổ Lóa; on the December solstice only 45.5°. Sunrise swings from 64° ENE in June to 115° ESE in December — a 50° 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
January06:3612:0717:3911 h 03 min49.0°
February06:2312:1017:5711 h 34 min58.3°
March06:0012:0318:0712 h 08 min69.1°
April05:3311:5518:1712 h 44 min80.7°
May05:1611:5318:2913 h 13 min89.1°
June05:1511:5818:4013 h 25 min87.7°
July05:2512:0218:3913 h 14 min89.3°
August05:3711:5918:2212 h 45 min81.0°
September05:4511:4917:5412 h 09 min69.6°
October05:5411:4117:2711 h 34 min58.2°
November06:1011:4217:1311 h 03 min49.0°
December06:2811:5417:1910 h 51 min45.5°

A year of daylight in Cổ Lóa

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 Cổ Lóa

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

16°collects the most energy over a year: 1123 kWh per kWp.

38°gives the most in the darkest month — the one an off-grid system is sized for.

40%50%60%70%80%90%100%0°10°20°30°40°50°60°70°80°90°Best year-round 16°Best worst-month 38°70°Yearly energyWorst-month energy
  • Yearly energy
  • Worst-month energy
TiltkWh/kWp per yearShare of best yearJanuary kWh/kWp/dayBest ÷ worst month
0°109297%1.862.1×
15°1123100%2.081.8×
16° year-round best1123100%2.091.8×
21° = latitude1119100%2.141.7×
30°109798%2.191.6×
38° off-grid best106094%2.211.5×
45°101690%2.191.5×
60°88679%2.081.5×
70°77769%1.941.6×
90°54749%1.552.0×

A fixed array in Cổ Lóa produces the most over a year at 16°. The design month for an off-grid system is January: at 38° it makes 2.21 kWh per kWp a day, 6% more than at 16°, and costs 6% of the yearly total. Why steep panels win winter.

Off-grid solar in Cổ Lóa at 70°

Daily energy of 1 kWp by month. Bars: panels at 70°. Line: panels at 16° (year-round best).

012345January: 1.94 (70°)1.9JanFebruary: 1.93 (70°)1.9FebMarch: 1.78 (70°)1.8MarApril: 1.90 (70°)1.9AprMay: 1.90 (70°)1.9MayJune: 1.85 (70°)1.8JunJuly: 1.83 (70°)1.8JulAugust: 2.05 (70°)2.0AugSeptember: 2.46 (70°)2.5SepOctober: 2.63 (70°)2.6OctNovember: 2.84 (70°)2.8NovDecember: 2.43 (70°)2.4Dec16°
MonthSun hours, flatSun hours at 70°kWh/kWp/day at 70°at 16°Mean temp.
January2.302.311.942.0915.4 °C
February2.682.321.932.3217.9 °C
March2.942.181.782.4221.0 °C
April3.812.361.903.0224.6 °C
May4.842.391.903.7027.2 °C
June5.022.331.853.7728.2 °C
July4.872.311.833.6728.2 °C
August4.612.562.053.5827.8 °C
September4.463.052.463.6226.7 °C
October3.793.212.633.2623.8 °C
November3.273.412.843.0020.4 °C
December2.592.872.432.4416.1 °C
Year3.77 avg2.61 avg777 kWh1123 kWh

Sizing example. To run a 1 kWh-per-day load through March on LiFePO4 batteries (charge controller, battery and inverter losses included) you need about 660 Wp of panels at 70°, versus 560 Wp at 16°. Here the lower tilt is the better winter choice — the sun stays high enough. Size your own system.

Row spacing in Cổ Lóa

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.

2.8 mrow pitch at 70°

2.5 mrow pitch at 16°

Row spacing calculator

How Cổ Lóa compares in Vietnam

Against the other 306 places in Vietnam with climate data, for a fixed array at its best angle.

272ndof 307 places in Vietnam for sunshine, shared: 3.77 peak sun hours a day on flat ground.

−15%solar energy a year compared with the average place in Vietnam: 1,123 against 1,320 kWh per kWp.

+40 mindaylight on the longest day, compared with Ho Chi Minh City: 13 h 25 min against 12 h 46 min.

16°best year-round tilt here; across Vietnam it runs from 9° in Vĩnh Châu to 21° in Dien Bien Phu.

Of the 307 places in Vietnam, Phú Quý gets the most sun (5.45 peak sun hours a day) and Thị Trấn Thất Khê and one other place the least (3.61); Cổ Lóa ranks joint 272nd. In its darkest month, March, 1 kWp of off-grid panels at 70° makes 1.78 kWh a day here, against 1.53 kWh on average in Vietnam. The shortest day lasts 10 h 51 min, −39 min compared with Ho Chi Minh City.

The sunniest places in Vietnam

Solar forecast for Cổ Lóa, 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 Cổ Lóa

What is the best solar panel angle in Cổ Lóa?
For a fixed array facing south, the best year-round tilt in Cổ Lóa is 16°, worth about 1123 kWh per kWp a year. An off-grid system that has to get through January does better at about 38°.
What time is sunrise and sunset in Cổ Lóa today?
On 25 October 2026 the sun rises at 05:55 and sets at 17:25 local time (UTC+7), giving 11 h 29 min of daylight. Solar noon is at 11:40.
How many peak sun hours does Cổ Lóa get?
On a flat surface 3.8 hours a day averaged over the year, from 2.3 in January to 5.0 in June. Panels tilted at 70° receive 2.2 sun hours a day in March.
How high does the sun get in Cổ Lóa?
At solar noon the sun stands 87.7° above the horizon on the June solstice and 45.5° on the December solstice.
Is Cổ Lóa a good place for solar panels?
With 3.8 peak sun hours a day on flat ground, Cổ Lóa ranks joint 272nd of 307 places in Vietnam for sunshine. A 1 kWp array at the best angle (16°) makes about 1,123 kWh a year here, 15% less than the average place in Vietnam.

Places near Cổ Lóa

All places in Vietnam

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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.