Solarposition.org

Niigata · Japan · 38.08° N · 138.44° E

Solar position in Ryōtsu-minato

Sun position, daylight and the best solar panel angle for Ryōtsu-minato — computed for 38.08° N, 138.44° E, 4 m above sea level.

Sunrise today06:04105° ESE
Sunset today16:55255° WSW
Best panel angle28°year-round, facing south
Off-grid angle57°best for the darkest month

The sun right now

Azimuth180.0°
Elevation39.9°
At solar noon, 11:30Open on the sun map

Sun in Ryōtsu-minato today

Sunday, 25 October 2026 · local time UTC+9

EventTimeDirection / height
Astronomical dawn04:35sun 18° below horizon
Nautical dawn05:0612° below
Civil dawn05:376° below
Sunrise06:04105° ESE
Golden hour ends06:40sun 6° up
Solar noon11:3039.9° high
Golden hour starts16:19sun 6° up
Sunset16:55255° WSW
Civil dusk17:226° below
Nautical dusk17:5312° below
Astronomical dusk18:2418° below
Day length10 h 52 min

Sun path diagram for Ryōtsu-minato

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 solstice5678910111213141516171819EquinoxDecember solstice8910111213141516Today
  • June solstice
  • Equinox
  • December solstice
  • Today

On the June solstice the sun reaches 75.4° at solar noon in Ryōtsu-minato; on the December solstice only 28.5°. Sunrise swings from 59° ENE in June to 120° ESE in December — a 61° 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
January06:5811:5716:569 h 58 min32.0°
February06:2912:0017:3011 h 01 min41.4°
March05:4911:5317:5812 h 10 min52.1°
April05:0311:4518:2713 h 24 min63.8°
May04:3111:4218:5414 h 23 min72.1°
June04:2311:4719:1214 h 49 min75.4°
July04:3911:5219:0514 h 26 min72.4°
August05:0611:4918:3213 h 26 min64.1°
September05:3211:3917:4512 h 13 min52.7°
October06:0011:3017:0111 h 01 min41.3°
November06:3211:3116:309 h 58 min32.1°
December06:5811:4416:299 h 31 min28.5°

A year of daylight in Ryōtsu-minato

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 Ryōtsu-minato

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

28°collects the most energy over a year: 1160 kWh per kWp.

57°gives the most in the darkest month — the one an off-grid system is sized for.

50%60%70%80%90%100%0°10°20°30°40°50°60°70°80°90°Best year-round 28°Best worst-month 57°70°Yearly energyWorst-month energy
  • Yearly energy
  • Worst-month energy
TiltkWh/kWp per yearShare of best yearDecember kWh/kWp/dayBest ÷ worst month
0°104990%1.034.2×
15°113598%1.313.4×
28° year-round best1160100%1.492.9×
30°1160100%1.522.8×
38° = latitude114799%1.592.6×
45°112297%1.642.4×
57° off-grid best104990%1.672.2×
60°102588%1.672.1×
70°93080%1.631.9×
90°68759%1.441.7×

A fixed array in Ryōtsu-minato produces the most over a year at 28°. The design month for an off-grid system is December: at 57° it makes 1.67 kWh per kWp a day, 12% more than at 28°, and costs 10% of the yearly total. Why steep panels win winter.

Off-grid solar in Ryōtsu-minato at 70°

Daily energy of 1 kWp by month. Bars: panels at 70°. Line: panels at 28° (year-round best).

012345January: 1.73 (70°)1.7JanFebruary: 2.28 (70°)2.3FebMarch: 3.00 (70°)3.0MarApril: 3.13 (70°)3.1AprMay: 2.84 (70°)2.8MayJune: 2.57 (70°)2.6JunJuly: 2.38 (70°)2.4JulAugust: 2.88 (70°)2.9AugSeptember: 2.97 (70°)3.0SepOctober: 2.91 (70°)2.9OctNovember: 2.27 (70°)2.3NovDecember: 1.63 (70°)1.6Dec28°
MonthSun hours, flatSun hours at 70°kWh/kWp/day at 70°at 28°Mean temp.
January1.471.971.731.644.5 °C
February2.242.582.282.364.4 °C
March3.493.413.003.446.4 °C
April4.643.623.134.1510.3 °C
May5.253.362.844.3015.1 °C
June5.303.112.574.1319.5 °C
July4.762.932.383.6923.5 °C
August5.003.552.884.0925.8 °C
September3.993.612.973.6022.9 °C
October2.993.462.913.0617.8 °C
November1.892.652.272.1412.5 °C
December1.301.881.631.497.3 °C
Year3.53 avg3.01 avg930 kWh1160 kWh

Sizing example. To run a 1 kWh-per-day load through December on LiFePO4 batteries (charge controller, battery and inverter losses included) you need about 720 Wp of panels at 70°, versus 790 Wp at 28°. The steep array is 8% smaller for the same winter. Size your own system.

Row spacing in Ryōtsu-minato

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.

4.7 mrow pitch at 70°

3.7 mrow pitch at 28°

Row spacing calculator

How Ryōtsu-minato compares in Japan

Against the other 1,215 places in Japan with climate data, for a fixed array at its best angle.

1070thof 1,216 places in Japan for sunshine, shared: 3.53 peak sun hours a day on flat ground.

−10%solar energy a year compared with the average place in Japan: 1,160 against 1,284 kWh per kWp.

+14 mindaylight on the longest day, compared with Tokyo: 14 h 49 min against 14 h 35 min.

28°best year-round tilt here; across Japan it runs from 17° in Miyakojima to 41° in Kushiro.

Of the 1,216 places in Japan, Miyakojima gets the most sun (4.34 peak sun hours a day) and Wakkanai and one other place the least (3.17); Ryōtsu-minato ranks joint 1070th. In its darkest month, December, 1 kWp of off-grid panels at 70° makes 1.63 kWh a day here, against 2.14 kWh on average in Japan. The shortest day lasts 9 h 31 min, −13 min compared with Tokyo.

The sunniest places in Japan

Solar forecast for Ryōtsu-minato, 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 Ryōtsu-minato

What is the best solar panel angle in Ryōtsu-minato?
For a fixed array facing south, the best year-round tilt in Ryōtsu-minato is 28°, worth about 1160 kWh per kWp a year. An off-grid system that has to get through December does better at about 57°.
What time is sunrise and sunset in Ryōtsu-minato today?
On 25 October 2026 the sun rises at 06:04 and sets at 16:55 local time (UTC+9), giving 10 h 52 min of daylight. Solar noon is at 11:30.
How many peak sun hours does Ryōtsu-minato get?
On a flat surface 3.5 hours a day averaged over the year, from 1.3 in December to 5.3 in June. Panels tilted at 70° receive 1.9 sun hours a day in December.
How high does the sun get in Ryōtsu-minato?
At solar noon the sun stands 75.4° above the horizon on the June solstice and 28.5° on the December solstice.
Is Ryōtsu-minato a good place for solar panels?
With 3.5 peak sun hours a day on flat ground, Ryōtsu-minato ranks joint 1070th of 1,216 places in Japan for sunshine. A 1 kWp array at the best angle (28°) makes about 1,160 kWh a year here, 10% less than the average place in Japan.

Places near Ryōtsu-minato

All places in Japan

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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.