Urban Municipality of Koper · Slovenia · 45.55° N · 13.73° E
Solar position in Koper
Sun position, daylight and the best solar panel angle for Koper — computed for 45.55° N, 13.73° E, 12 m above sea level.
The sun right now
Sun in Koper today
Saturday, 24 October 2026 · local time UTC+2
| Event | Time | Direction / height |
|---|---|---|
| Astronomical dawn | 05:54 | sun 18° below horizon |
| Nautical dawn | 06:28 | 12° below |
| Civil dawn | 07:03 | 6° below |
| Sunrise | 07:33 | 106° ESE |
| Golden hour ends | 08:14 | sun 6° up |
| Solar noon | 12:49 | 32.6° high |
| Golden hour starts | 17:23 | sun 6° up |
| Sunset | 18:04 | 254° WSW |
| Civil dusk | 18:34 | 6° below |
| Nautical dusk | 19:09 | 12° below |
| Astronomical dusk | 19:43 | 18° below |
| Day length | 10 h 31 min | |
Sun path diagram for Koper
Where the sun stands in the sky: the centre is straight overhead, the outer ring is the horizon. Numbers mark local clock hours.
- June solstice
- Equinox
- December solstice
- Today
On the June solstice the sun reaches 67.9° at solar noon in Koper; on the December solstice only 21.1°. Sunrise swings from 54° NE in June to 124° ESE in December — a 69° 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.
| Month | Sunrise | Solar noon | Sunset | Day length | Noon elevation |
|---|---|---|---|---|---|
| January | 07:37 | 12:16 | 16:55 | 9 h 18 min | 24.6° |
| February | 06:57 | 12:18 | 17:40 | 10 h 43 min | 34.0° |
| March | 06:06 | 12:12 | 18:18 | 12 h 12 min | 44.8° |
| April | 06:09 | 13:03 | 19:58 | 13 h 49 min | 56.4° |
| May | 05:28 | 13:01 | 20:35 | 15 h 08 min | 64.7° |
| June | 05:16 | 13:06 | 20:57 | 15 h 42 min | 67.9° |
| July | 05:36 | 13:11 | 20:45 | 15 h 09 min | 64.9° |
| August | 06:12 | 13:08 | 20:02 | 13 h 50 min | 56.5° |
| September | 06:50 | 12:57 | 19:04 | 12 h 14 min | 45.1° |
| October | 07:29 | 12:49 | 18:09 | 10 h 40 min | 33.7° |
| November | 07:12 | 11:50 | 16:29 | 9 h 17 min | 24.5° |
| December | 07:42 | 12:03 | 16:24 | 8 h 42 min | 21.1° |
A year of daylight in Koper
Each column is one day of 2026. Bright: sun above the horizon; soft: civil twilight; line: solar noon. Steps are daylight saving time changes.
Best solar panel angle in Koper
Fixed array facing south (azimuth 180°). Energy per kWp from NASA POWER monthly climate, including clouds, temperature and snow reflection.
36°collects the most energy over a year: 1336 kWh per kWp.
68°gives the most in the darkest month — the one an off-grid system is sized for.
- Yearly energy
- Worst-month energy
| Tilt | kWh/kWp per year | Share of best year | December kWh/kWp/day | Best ÷ worst month |
|---|---|---|---|---|
| 0° | 1118 | 84% | 0.87 | 6.1× |
| 15° | 1260 | 94% | 1.33 | 4.1× |
| 30° | 1330 | 100% | 1.70 | 3.1× |
| 36° year-round best | 1336 | 100% | 1.82 | 2.8× |
| 45° | 1322 | 99% | 1.97 | 2.5× |
| 46° = latitude | 1319 | 99% | 1.98 | 2.4× |
| 60° | 1239 | 93% | 2.11 | 2.0× |
| 68° off-grid best | 1165 | 87% | 2.13 | 1.8× |
| 70° | 1144 | 86% | 2.13 | 1.8× |
| 90° | 877 | 66% | 1.98 | 1.5× |
A fixed array in Koper produces the most over a year at 36°. The design month for an off-grid system is December: at 68° it makes 2.13 kWh per kWp a day, 17% more than at 36°, and costs 13% of the yearly total. Why steep panels win winter.
Off-grid solar in Koper at 70°
Daily energy of 1 kWp by month. Bars: panels at 70°. Line: panels at 36° (year-round best).
| Month | Sun hours, flat | Sun hours at 70° | kWh/kWp/day at 70° | at 36° | Mean temp. |
|---|---|---|---|---|---|
| January | 1.32 | 2.56 | 2.28 | 2.01 | 3.2 °C |
| February | 2.16 | 3.36 | 2.98 | 2.86 | 3.8 °C |
| March | 3.43 | 4.08 | 3.59 | 3.83 | 7.2 °C |
| April | 4.69 | 4.19 | 3.61 | 4.43 | 11.6 °C |
| May | 5.72 | 4.08 | 3.44 | 4.75 | 16.1 °C |
| June | 6.46 | 4.09 | 3.39 | 5.00 | 20.5 °C |
| July | 6.58 | 4.31 | 3.55 | 5.14 | 22.9 °C |
| August | 5.65 | 4.56 | 3.76 | 4.89 | 22.7 °C |
| September | 4.05 | 4.34 | 3.65 | 4.11 | 18.2 °C |
| October | 2.54 | 3.54 | 3.03 | 3.03 | 13.6 °C |
| November | 1.44 | 2.53 | 2.19 | 2.00 | 9.1 °C |
| December | 1.13 | 2.41 | 2.13 | 1.82 | 4.7 °C |
| Year | 3.77 avg | 3.67 avg | 1144 kWh | 1336 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 550 Wp of panels at 70°, versus 650 Wp at 36°. The steep array is 14% smaller for the same winter. Size your own system.
Row spacing in Koper
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.
6.5 mrow pitch at 70°
5.3 mrow pitch at 36°
How Koper compares in Slovenia
Against the other 8 places in Slovenia with climate data, for a fixed array at its best angle.
1stof 9 places in Slovenia for sunshine: 3.77 peak sun hours a day on flat ground.
+5%solar energy a year compared with the average place in Slovenia: 1,336 against 1,273 kWh per kWp.
−4 mindaylight on the longest day, compared with Ljubljana: 15 h 42 min against 15 h 46 min.
36°best year-round tilt here; across Slovenia it runs from 36° in Koper to 38° in Maribor.
Koper gets the most sun of the 9 places in Slovenia (3.77 peak sun hours a day); the least sunny is Maribor with 3.47. In its darkest month, December, 1 kWp of off-grid panels at 70° makes 2.13 kWh a day here, against 2.10 kWh on average in Slovenia. The shortest day lasts 8 h 42 min, +4 min compared with Ljubljana.
Solar forecast for Koper, next 48 hours
Expected output of 1 kWp at 70°, computed from the ICON-EU weather model of the Deutscher Wetterdienst (DWD), Europe.
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Questions about the sun in Koper
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Places near Koper
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A free, live card for Koper: where the sun is right now on today's path, a countdown to sunset or sunrise, the daylight change, the moon phase at night and the best panel angle.
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.