Pennsylvania · United States · 40.05° N · 75.36° W
Solar position in Radnor
Sun position, daylight and the best solar panel angle for Radnor — computed for 40.05° N, 75.36° W, 132 m above sea level.
The sun right now
Sun in Radnor today
Saturday, 24 October 2026 · local time UTC−4
| Event | Time | Direction / height |
|---|---|---|
| Astronomical dawn | 05:50 | sun 18° below horizon |
| Nautical dawn | 06:22 | 12° below |
| Civil dawn | 06:54 | 6° below |
| Sunrise | 07:21 | 105° ESE |
| Golden hour ends | 07:59 | sun 6° up |
| Solar noon | 12:45 | 38.1° high |
| Golden hour starts | 17:31 | sun 6° up |
| Sunset | 18:08 | 255° WSW |
| Civil dusk | 18:36 | 6° below |
| Nautical dusk | 19:08 | 12° below |
| Astronomical dusk | 19:39 | 18° below |
| Day length | 10 h 47 min | |
Sun path diagram for Radnor
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 73.4° at solar noon in Radnor; on the December solstice only 26.5°. Sunrise swings from 58° ENE in June to 120° ESE in December — a 63° 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 | 07:18 | 12:12 | 17:07 | 9 h 49 min | 30.2° |
| February | 06:46 | 12:15 | 17:44 | 10 h 58 min | 39.6° |
| March | 07:03 | 13:08 | 19:14 | 12 h 11 min | 50.4° |
| April | 06:14 | 13:00 | 19:46 | 13 h 31 min | 62.0° |
| May | 05:40 | 12:58 | 20:15 | 14 h 35 min | 70.2° |
| June | 05:32 | 13:03 | 20:33 | 15 h 01 min | 73.4° |
| July | 05:50 | 13:07 | 20:25 | 14 h 35 min | 70.3° |
| August | 06:18 | 13:04 | 19:49 | 13 h 31 min | 61.9° |
| September | 06:48 | 12:54 | 19:00 | 12 h 12 min | 50.5° |
| October | 07:18 | 12:45 | 18:13 | 10 h 55 min | 39.1° |
| November | 06:53 | 11:47 | 16:40 | 9 h 47 min | 30.0° |
| December | 07:19 | 11:59 | 16:39 | 9 h 19 min | 26.5° |
A year of daylight in Radnor
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 Radnor
Fixed array facing south (azimuth 180°). Energy per kWp from NASA POWER monthly climate, including clouds, temperature and snow reflection.
35°collects the most energy over a year: 1390 kWh per kWp.
63°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° | 1182 | 85% | 1.34 | 3.6× |
| 15° | 1322 | 95% | 1.89 | 2.6× |
| 30° | 1386 | 100% | 2.32 | 2.0× |
| 35° year-round best | 1390 | 100% | 2.43 | 1.9× |
| 40° = latitude | 1385 | 100% | 2.53 | 1.7× |
| 45° | 1371 | 99% | 2.60 | 1.6× |
| 60° | 1278 | 92% | 2.73 | 1.4× |
| 63° off-grid best | 1250 | 90% | 2.73 | 1.4× |
| 70° | 1176 | 85% | 2.71 | 1.4× |
| 90° | 896 | 64% | 2.46 | 1.9× |
A fixed array in Radnor produces the most over a year at 35°. The design month for an off-grid system is December: at 63° it makes 2.73 kWh per kWp a day, 12% more than at 35°, and costs 10% of the yearly total. Why steep panels win winter.
Off-grid solar in Radnor at 70°
Daily energy of 1 kWp by month. Bars: panels at 70°. Line: panels at 35° (year-round best).
| Month | Sun hours, flat | Sun hours at 70° | kWh/kWp/day at 70° | at 35° | Mean temp. |
|---|---|---|---|---|---|
| January snow | 1.94 | 3.47 | 3.15 | 2.81 | -1.0 °C |
| February snow | 2.81 | 4.09 | 3.70 | 3.57 | 0.0 °C |
| March | 3.74 | 4.02 | 3.57 | 4.00 | 4.2 °C |
| April | 4.88 | 3.95 | 3.41 | 4.43 | 10.5 °C |
| May | 5.45 | 3.52 | 2.96 | 4.35 | 16.2 °C |
| June | 6.01 | 3.47 | 2.86 | 4.48 | 21.4 °C |
| July | 6.07 | 3.66 | 2.98 | 4.57 | 24.4 °C |
| August | 5.28 | 3.87 | 3.18 | 4.35 | 23.8 °C |
| September | 4.32 | 4.19 | 3.50 | 4.14 | 20.2 °C |
| October | 3.06 | 3.95 | 3.39 | 3.50 | 13.5 °C |
| November | 2.22 | 3.75 | 3.30 | 3.06 | 7.1 °C |
| December | 1.65 | 3.03 | 2.71 | 2.43 | 2.0 °C |
| Year | 3.96 avg | 3.74 avg | 1176 kWh | 1390 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 430 Wp of panels at 70°, versus 490 Wp at 35°. The steep array is 10% smaller for the same winter. Size your own system.
Row spacing in Radnor
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.
5.0 mrow pitch at 70°
4.3 mrow pitch at 35°
How Radnor 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.
2024thof 3,121 places in the United States for sunshine, shared: 3.96 peak sun hours a day on flat ground.
−8%solar energy a year compared with the average place in the United States: 1,390 against 1,515 kWh per kWp.
−4 mindaylight on the longest day, compared with New York City: 15 h 01 min against 15 h 06 min.
35°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); Radnor ranks joint 2024th. In its darkest month, December, 1 kWp of off-grid panels at 70° makes 2.71 kWh a day here, against 2.55 kWh on average in the United States. The shortest day lasts 9 h 19 min, +4 min compared with New York City.
Solar forecast for Radnor, 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 Radnor
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Places near Radnor
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A free, live card for Radnor: 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.