Illinois · United States · 42.35° N · 88.09° W
Solar position in Round Lake
Sun position, daylight and the best solar panel angle for Round Lake — computed for 42.35° N, 88.09° W, 243 m above sea level.
The sun right now
Sun in Round Lake today
Saturday, 24 October 2026 · local time UTC−5
| Event | Time | Direction / height |
|---|---|---|
| Astronomical dawn | 05:41 | sun 18° below horizon |
| Nautical dawn | 06:14 | 12° below |
| Civil dawn | 06:47 | 6° below |
| Sunrise | 07:16 | 105° ESE |
| Golden hour ends | 07:55 | sun 6° up |
| Solar noon | 12:36 | 35.7° high |
| Golden hour starts | 17:17 | sun 6° up |
| Sunset | 17:56 | 254° WSW |
| Civil dusk | 18:25 | 6° below |
| Nautical dusk | 18:57 | 12° below |
| Astronomical dusk | 19:30 | 18° below |
| Day length | 10 h 40 min | |
Sun path diagram for Round Lake
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 71.1° at solar noon in Round Lake; on the December solstice only 24.2°. Sunrise swings from 57° ENE in June to 122° ESE in December — a 65° 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 | 07:15 | 12:03 | 16:52 | 9 h 37 min | 27.9° |
| February | 06:39 | 12:06 | 17:32 | 10 h 52 min | 37.3° |
| March | 06:53 | 12:59 | 19:05 | 12 h 12 min | 48.1° |
| April | 06:01 | 12:51 | 19:40 | 13 h 39 min | 59.7° |
| May | 05:25 | 12:49 | 20:13 | 14 h 48 min | 67.9° |
| June | 05:15 | 12:54 | 20:32 | 15 h 17 min | 71.1° |
| July | 05:34 | 12:58 | 20:22 | 14 h 48 min | 68.0° |
| August | 06:06 | 12:55 | 19:44 | 13 h 38 min | 59.6° |
| September | 06:38 | 12:45 | 18:51 | 12 h 12 min | 48.2° |
| October | 07:12 | 12:36 | 18:00 | 10 h 48 min | 36.8° |
| November | 06:50 | 11:38 | 16:25 | 9 h 35 min | 27.6° |
| December | 07:18 | 11:50 | 16:22 | 9 h 05 min | 24.2° |
A year of daylight in Round Lake
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 Round Lake
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: 1355 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° | 1144 | 84% | 1.10 | 4.5× |
| 15° | 1283 | 95% | 1.59 | 3.2× |
| 30° | 1350 | 100% | 1.99 | 2.4× |
| 36° year-round best | 1355 | 100% | 2.12 | 2.2× |
| 42° = latitude | 1349 | 100% | 2.23 | 2.0× |
| 45° | 1341 | 99% | 2.28 | 1.9× |
| 60° | 1258 | 93% | 2.43 | 1.6× |
| 68° off-grid best | 1185 | 87% | 2.45 | 1.5× |
| 70° | 1164 | 86% | 2.45 | 1.5× |
| 90° | 901 | 66% | 2.30 | 1.8× |
A fixed array in Round Lake produces the most over a year at 36°. The design month for an off-grid system is December: at 68° it makes 2.45 kWh per kWp a day, 16% more than at 36°, and costs 13% of the yearly total. Why steep panels win winter.
Off-grid solar in Round Lake 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 snow | 1.60 | 3.07 | 2.82 | 2.43 | -4.7 °C |
| February snow | 2.49 | 3.94 | 3.61 | 3.33 | -3.8 °C |
| March | 3.55 | 3.93 | 3.52 | 3.89 | 1.8 °C |
| April | 4.65 | 3.91 | 3.42 | 4.32 | 7.4 °C |
| May | 5.39 | 3.65 | 3.11 | 4.41 | 13.0 °C |
| June | 6.06 | 3.67 | 3.05 | 4.62 | 19.0 °C |
| July | 6.17 | 3.88 | 3.19 | 4.73 | 22.6 °C |
| August | 5.35 | 4.08 | 3.37 | 4.50 | 22.2 °C |
| September | 4.31 | 4.40 | 3.70 | 4.27 | 18.4 °C |
| October | 2.81 | 3.75 | 3.25 | 3.32 | 11.1 °C |
| November | 1.85 | 3.18 | 2.82 | 2.61 | 4.4 °C |
| December snow | 1.35 | 2.71 | 2.45 | 2.12 | -1.7 °C |
| Year | 3.81 avg | 3.68 avg | 1164 kWh | 1355 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 480 Wp of panels at 70°, versus 560 Wp at 36°. The steep array is 13% smaller for the same winter. Size your own system.
Row spacing in Round Lake
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.
5.6 mrow pitch at 70°
4.7 mrow pitch at 36°
How Round Lake compares in the United States
Against the other 3,120 places in the United States with climate data, for a fixed array at its best angle.
2643rdof 3,121 places in the United States for sunshine, shared: 3.81 peak sun hours a day on flat ground.
−11%solar energy a year compared with the average place in the United States: 1,355 against 1,515 kWh per kWp.
+11 mindaylight on the longest day, compared with New York City: 15 h 17 min against 15 h 06 min.
36°best year-round tilt here; across the United States it runs from 18° in Honolulu to 53° in Fairbanks.
Of the 3,121 places in the United States, Fortuna Foothills and 2 other places get the most sun (5.96 peak sun hours a day) and Juneau the least (2.38); Round Lake ranks joint 2643rd. In its darkest month, December, 1 kWp of off-grid panels at 70° makes 2.45 kWh a day here, against 2.55 kWh on average in the United States. The shortest day lasts 9 h 05 min, −11 min compared with New York City.
Solar forecast for Round Lake, 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 Round Lake
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Places near Round Lake
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A free, live card for Round Lake: 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.