Zacatecas · Mexico · 23.83° N · 103.03° W
Solar position in Río Grande
Sun position, daylight and the best solar panel angle for Río Grande — computed for 23.83° N, 103.03° W, 1859 m above sea level.
The sun right now
Sun in Río Grande today
Saturday, 24 October 2026 · local time UTC−6
| Event | Time | Direction / height |
|---|---|---|
| Astronomical dawn | 05:37 | sun 18° below horizon |
| Nautical dawn | 06:04 | 12° below |
| Civil dawn | 06:30 | 6° below |
| Sunrise | 06:53 | 103° ESE |
| Golden hour ends | 07:24 | sun 6° up |
| Solar noon | 12:36 | 54.2° high |
| Golden hour starts | 17:47 | sun 6° up |
| Sunset | 18:18 | 257° WSW |
| Civil dusk | 18:41 | 6° below |
| Nautical dusk | 19:08 | 12° below |
| Astronomical dusk | 19:34 | 18° below |
| Day length | 11 h 24 min | |
Sun path diagram for Río Grande
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 89.6° at solar noon in Río Grande; on the December solstice only 42.7°. Sunrise swings from 64° ENE in June to 115° ESE in December — a 52° 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 | 07:36 | 13:03 | 18:31 | 10 h 55 min | 46.4° |
| February | 07:20 | 13:05 | 18:51 | 11 h 30 min | 55.8° |
| March | 06:54 | 12:59 | 19:03 | 12 h 09 min | 66.6° |
| April | 06:25 | 12:50 | 19:16 | 12 h 51 min | 78.2° |
| May | 06:07 | 12:48 | 19:30 | 13 h 23 min | 86.5° |
| June | 06:05 | 12:54 | 19:42 | 13 h 37 min | 89.6° |
| July | 06:16 | 12:58 | 19:40 | 13 h 23 min | 86.5° |
| August | 06:30 | 12:55 | 19:20 | 12 h 50 min | 78.1° |
| September | 06:40 | 12:45 | 18:49 | 12 h 09 min | 66.7° |
| October | 06:52 | 12:36 | 18:20 | 11 h 28 min | 55.3° |
| November | 07:11 | 12:37 | 18:04 | 10 h 54 min | 46.1° |
| December | 07:30 | 12:50 | 18:10 | 10 h 40 min | 42.7° |
A year of daylight in Río Grande
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 Río Grande
Fixed array facing south (azimuth 180°). Energy per kWp from NASA POWER monthly climate, including clouds, temperature and snow reflection.
24°collects the most energy over a year: 1947 kWh per kWp.
20°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 | July kWh/kWp/day | Best ÷ worst month |
|---|---|---|---|---|
| 0° | 1798 | 92% | 5.33 | 1.7× |
| 15° | 1926 | 99% | 5.07 | 1.3× |
| 20° off-grid best | 1943 | 100% | 4.92 | 1.3× |
| 24° year-round best = latitude | 1947 | 100% | 4.78 | 1.3× |
| 30° | 1938 | 100% | 4.53 | 1.3× |
| 45° | 1835 | 94% | 3.76 | 1.6× |
| 60° | 1625 | 83% | 2.81 | 2.1× |
| 70° | 1434 | 74% | 2.14 | 2.8× |
| 90° | 989 | 51% | 1.08 | 4.7× |
A fixed array in Río Grande produces the most over a year at 24°. The design month for an off-grid system is July: at 20° it makes 4.92 kWh per kWp a day, 3% more than at 24°, and costs 0% of the yearly total. Why steep panels win winter.
Off-grid solar in Río Grande at 70°
Daily energy of 1 kWp by month. Bars: panels at 70°. Line: panels at 24° (year-round best).
| Month | Sun hours, flat | Sun hours at 70° | kWh/kWp/day at 70° | at 24° | Mean temp. |
|---|---|---|---|---|---|
| January | 4.57 | 6.27 | 5.43 | 5.18 | 10.9 °C |
| February | 5.57 | 6.17 | 5.31 | 5.74 | 13.0 °C |
| March | 6.67 | 5.47 | 4.66 | 6.11 | 15.7 °C |
| April | 7.36 | 4.07 | 3.41 | 5.94 | 19.2 °C |
| May | 7.51 | 2.94 | 2.42 | 5.50 | 21.9 °C |
| June | 7.04 | 2.45 | 1.99 | 4.97 | 22.6 °C |
| July | 6.56 | 2.61 | 2.14 | 4.78 | 21.1 °C |
| August | 6.51 | 3.27 | 2.70 | 5.05 | 20.9 °C |
| September | 5.65 | 4.01 | 3.36 | 4.84 | 19.2 °C |
| October | 5.58 | 5.57 | 4.71 | 5.44 | 17.4 °C |
| November | 4.90 | 6.48 | 5.55 | 5.42 | 13.8 °C |
| December | 4.36 | 6.41 | 5.54 | 5.09 | 11.4 °C |
| Year | 6.03 avg | 4.63 avg | 1434 kWh | 1947 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 590 Wp of panels at 70°, versus 250 Wp at 24°. Here the lower tilt is the better winter choice — the sun stays high enough. Size your own system.
Row spacing in Río Grande
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.
3.0 mrow pitch at 70°
2.8 mrow pitch at 24°
How Río Grande compares in Mexico
Against the other 624 places in Mexico with climate data, for a fixed array at its best angle.
14thof 625 places in Mexico for sunshine, shared: 6.03 peak sun hours a day on flat ground.
+11%solar energy a year compared with the average place in Mexico: 1,947 against 1,754 kWh per kWp.
+18 mindaylight on the longest day, compared with Mexico City: 13 h 37 min against 13 h 18 min.
24°best year-round tilt here; across Mexico it runs from 15° in Coatzacoalcos to 30° in Tijuana.
Of the 625 places in Mexico, Ciudad Constitución gets the most sun (6.12 peak sun hours a day) and Poza Rica de Hidalgo and one other place the least (4.59); Río Grande ranks joint 14th. In its darkest month, June, 1 kWp of off-grid panels at 70° makes 1.99 kWh a day here, against 1.82 kWh on average in Mexico. The shortest day lasts 10 h 40 min, −18 min compared with Mexico City.
Solar forecast for Río Grande, 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 Río Grande
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Places near Río Grande
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A free, live card for Río Grande: 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.