Argentina · 31.54° S · 68.53° W
Solar position in San Juan
Sun position, daylight and the best solar panel angle for San Juan — computed for 31.54° S, 68.53° W, 646 m above sea level.
The sun right now
Sun in San Juan today
Saturday, 24 October 2026 · local time UTC−3
| Event | Time | Direction / height |
|---|---|---|
| Astronomical dawn | 05:18 | sun 18° below horizon |
| Nautical dawn | 05:49 | 12° below |
| Civil dawn | 06:19 | 6° below |
| Sunrise | 06:44 | 104° ESE |
| Golden hour ends | 07:17 | sun 6° up |
| Solar noon | 13:18 | 70.4° high |
| Golden hour starts | 19:19 | sun 6° up |
| Sunset | 19:52 | 255° WSW |
| Civil dusk | 20:17 | 6° below |
| Nautical dusk | 20:47 | 12° below |
| Astronomical dusk | 21:18 | 18° below |
| Day length | 13 h 08 min | |
Sun path diagram for San Juan
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 35.0° at solar noon in San Juan; on the December solstice only 81.9°. Sunrise swings from 63° ENE in June to 118° ESE in December — a 56° 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 | 06:49 | 13:45 | 20:40 | 13 h 51 min | 78.3° |
| February | 07:17 | 13:47 | 20:17 | 13 h 00 min | 68.8° |
| March | 07:38 | 13:41 | 19:43 | 12 h 06 min | 58.0° |
| April | 07:58 | 13:32 | 19:06 | 11 h 08 min | 46.5° |
| May | 08:18 | 13:30 | 18:42 | 10 h 24 min | 38.2° |
| June | 08:33 | 13:35 | 18:38 | 10 h 05 min | 35.0° |
| July | 08:29 | 13:40 | 18:52 | 10 h 23 min | 38.1° |
| August | 08:03 | 13:37 | 19:11 | 11 h 08 min | 46.5° |
| September | 07:24 | 13:27 | 19:29 | 12 h 05 min | 58.0° |
| October | 06:47 | 13:18 | 19:49 | 13 h 02 min | 69.3° |
| November | 06:24 | 13:20 | 20:16 | 13 h 52 min | 78.5° |
| December | 06:25 | 13:32 | 20:38 | 14 h 13 min | 81.9° |
A year of daylight in San Juan
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 San Juan
Fixed array facing north (azimuth 0°). Energy per kWp from NASA POWER monthly climate, including clouds, temperature and snow reflection.
30°collects the most energy over a year: 1958 kWh per kWp.
46°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 | May kWh/kWp/day | Best ÷ worst month |
|---|---|---|---|---|
| 0° | 1721 | 88% | 2.86 | 2.6× |
| 15° | 1898 | 97% | 3.73 | 1.8× |
| 30° year-round best | 1958 | 100% | 4.35 | 1.4× |
| 32° = latitude | 1956 | 100% | 4.41 | 1.4× |
| 45° | 1897 | 97% | 4.69 | 1.2× |
| 46° off-grid best | 1889 | 96% | 4.71 | 1.2× |
| 60° | 1722 | 88% | 4.74 | 1.5× |
| 70° | 1547 | 79% | 4.60 | 1.9× |
| 90° | 1099 | 56% | 3.94 | 3.9× |
A fixed array in San Juan produces the most over a year at 30°. The design month for an off-grid system is May: at 46° it makes 4.71 kWh per kWp a day, 8% more than at 30°, and costs 4% of the yearly total. Why steep panels win winter.
Off-grid solar in San Juan at 70°
Daily energy of 1 kWp by month. Bars: panels at 70°. Line: panels at 30° (year-round best).
| Month | Sun hours, flat | Sun hours at 70° | kWh/kWp/day at 70° | at 30° | Mean temp. |
|---|---|---|---|---|---|
| January | 8.00 | 3.58 | 2.92 | 5.68 | 25.4 °C |
| February | 7.14 | 4.39 | 3.60 | 5.68 | 24.1 °C |
| March | 6.00 | 5.20 | 4.33 | 5.51 | 21.4 °C |
| April | 4.69 | 5.74 | 4.86 | 5.12 | 17.1 °C |
| May | 3.51 | 5.34 | 4.60 | 4.35 | 12.5 °C |
| June | 3.21 | 5.66 | 4.94 | 4.38 | 9.7 °C |
| July | 3.48 | 5.84 | 5.10 | 4.63 | 9.0 °C |
| August | 4.50 | 6.19 | 5.36 | 5.33 | 11.3 °C |
| September | 5.77 | 5.79 | 4.95 | 5.80 | 14.3 °C |
| October | 7.07 | 4.93 | 4.15 | 6.04 | 18.4 °C |
| November | 8.13 | 3.94 | 3.26 | 6.02 | 22.0 °C |
| December | 8.47 | 3.40 | 2.78 | 5.84 | 24.3 °C |
| Year | 5.82 avg | 5.00 avg | 1547 kWh | 1958 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 420 Wp of panels at 70°, versus 270 Wp at 30°. Here the lower tilt is the better winter choice — the sun stays high enough. Size your own system.
Row spacing in San Juan
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.
3.7 mrow pitch at 70°
3.3 mrow pitch at 30°
How San Juan compares in Argentina
Against the other 313 places in Argentina with climate data, for a fixed array at its best angle.
9thof 314 places in Argentina for sunshine, shared: 5.82 peak sun hours a day on flat ground.
+19%solar energy a year compared with the average place in Argentina: 1,958 against 1,639 kWh per kWp.
−16 mindaylight on the longest day, compared with Buenos Aires: 14 h 13 min against 14 h 29 min.
30°best year-round tilt here; across Argentina it runs from 21° in Tartagal to 44° in Río Gallegos.
Of the 314 places in Argentina, Belén gets the most sun (6.11 peak sun hours a day) and Ushuaia the least (2.59); San Juan ranks joint 9th. In its darkest month, December, 1 kWp of off-grid panels at 70° makes 2.78 kWh a day here, against 2.68 kWh on average in Argentina. The shortest day lasts 10 h 05 min, +15 min compared with Buenos Aires.
Solar forecast for San Juan, 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 San Juan
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Places near San Juan
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A free, live card for San Juan: 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.