United States · stargazing
Stargazing in Philadelphia
How dark Philadelphia's sky really is, which way to head to escape it, and a live seven-night forecast — scored honestly from cloud, moon and light pollution.
What you can actually see from Philadelphia
The sky over the city centre sits at about Bortle 9(17.05 mag/arcsec², 2024 atlas) — an approximation from modelled zenith brightness, not a field measurement (what each level means).
From the middle of Philadelphia the sky glows too brightly for the Milky Way to show at all. What the city does give you is the Moon, the bright planets — Jupiter, Saturn, Venus, Mars — and the few brightest stars and star clusters, which cut through light pollution regardless. Everything fainter — the Milky Way, galaxies, most nebulae, a rich meteor shower — needs you to leave the glow behind.
Which way to escape the glow
The fastest way out of Philadelphia's light dome is to head south-west. In that direction the atlas shows the sky darkening to around Bortle 4 — dark enough for the Milky Way — within roughly 250 km of the centre. That's also the way toward Sky Meadows State Park, the nearest certified dark-sky place (262.8 km out).
Directions and distances are sampled from the light-pollution atlas as the crow flies — real roads, terrain and a clear horizon still matter, so treat this as where to point the car, not a turn-by-turn route.
The next seven nights in Philadelphia
Loading the live forecast…
Dark-sky sites nearest Philadelphia
The closest DarkSky International certified places worth the drive, with their direction and straight-line distance from Philadelphia.
- Sky Meadows State Park
park · south-west · 262.8 km · Bortle ≈ 4
- Rappahannock County Park
park · south-west · 291.2 km · Bortle ≈ 4
- Cherry Springs State Park
park · north-west · 293.3 km · Bortle ≈ 3
The Orionid meteor shower from Philadelphia: 21–22 October 2026
The Orionids — fast meteors from Comet 1P/Halley, up to ~20 an hour under ideal dark skies (IMO) — peak overnight on 21–22 October 2026. From Philadelphia, the radiant in northern Orion climbs to about 66° above the southern horizon before dawn. Because 2026's peak lands under a bright ~80% waxing gibbous Moon, evening watching will disappoint — the productive window is the pre-dawn hours as the Moon sinks and sets.
Stacking Philadelphia's Bortle 9 inner-city glow on top of an ~80% Moon leaves only the occasional bright fireball from town. If the pre-dawn forecast is clear, use the escape route above for the dark window after moonset.
Because 21–22 October is within the 16-night forecast window, you can check Philadelphia's exact peak-night cloud cover and local moonset time on the Orionids 2026 live viewing forecast.
The Geminid meteor shower from Philadelphia: 13–14 December 2026
The Geminids — the year's richest shower, up to ~150 meteors an hour under ideal skies — peak on the night of 13–14 December 2026. The Moon cooperates this year: a ~21% crescent sets during the evening, leaving the main hours dark. That leaves the two local factors this page is about: cloud on the night, and how far you get from the city's glow.
From the Bortle 9 city centre only the brightest fireballs cut through the glow — the faint majority of Geminids needs darker sky. The escape routes and certified sites above are exactly what the peak night is for.
For scored peak-night conditions — cloud through the dark hours at your exact spot — open the Geminids 2026 live viewing forecast once 13 December comes within the 16-night horizon.
Plan the next 90 days from Philadelphia
Moon-free dark windows are astronomy — computable years ahead. Cloud is not: beyond the 16-night forecast nobody knows the weather, and we won't pretend to. What five years of observations can say is how often each month's nights actually stayed clear here. Both are below — read them for what they are.
- Oct 4–1714 moon-free nights61% of October nights here stayed clear (2021–2025)
- Nov 3–1513 moon-free nights65% of November nights here stayed clear (2021–2025)
- Dec 2–1413 moon-free nights44% of December nights here stayed clear (2021–2025)
- Dec 31 – Jan 1314 moon-free nights44% of December nights here stayed clear (2021–2025)
Clearest months in Philadelphia historically: June (66%), November (65%), July (63%).
Clear-night odds are ERA5 reanalysis statistics for 2021–2025 (CC BY 4.0) — historical frequency, not a forecast. Once a window comes within 16 nights, the live forecast above takes over with real cloud data.
Put Philadelphia's dark-sky nights on your calendar
Every month has a stretch of nights when the Moon leaves Philadelphia's dark hours essentially moon-free. Subscribe once and each window lands in your own calendar, about a year ahead — no account, no email.
moon & darkness geometry only — cloud can't be known this far out; check the live forecast above when a window gets close
Light pollution: David Lorenz, World Atlas 2024 (EOG VIIRS, CC BY 4.0), approximate. Cloud: Open-Meteo.com (CC BY 4.0). Dark-sky places: DarkSky International. Coordinates used are the city's public centre, not any personal location.