Northern Lights tonight in Boulogne-Billancourt

Tonight in Boulogne-Billancourt

Boulogne-Billancourt sits at a geomagnetic latitude of 50.4° N, so the aurora usually needs a Kp index of about 7 or higher before it rises above the northern horizon. Tonight's NOAA forecast peaks at Kp 3 (quiet) during the dark hours, 4.0 short of what Boulogne-Billancourt needs.

Open-Meteo expects about 65% cloud cover on average between 8 pm and 7 am local time, with 2 of 11 dark hours mostly clear (30% cloud or less).

The Moon is 100% illuminated (full moon), bright enough to wash out a faint aurora, so only a stronger display will stand out. For the best view look north, low on the horizon, from somewhere away from street lights.

Right now NOAA's OVATION model gives up to 0% chance of aurora in the part of the sky visible from Boulogne-Billancourt. OVATION is a short-range nowcast (30 to 90 minutes ahead), useful for deciding whether to step outside now.

3-day Kp forecast

None of the next 3 days reaches the Kp 7 that Boulogne-Billancourt needs. Kp is a global 0–9 index of geomagnetic activity, issued in 3-hour blocks (UTC); NOAA forecasts beyond 24 hours are uncertain, because storms are triggered by solar eruptions that take 1–3 days to arrive.

Why Boulogne-Billancourt needs Kp 7

The aurora forms in an oval around the geomagnetic pole, which sits in the Canadian Arctic (about 80.8° N, 72.8° W), not at the geographic pole. That is why the Kp a city needs depends on its geomagnetic rather than its geographic latitude. At Kp 0 the oval's edge is near 66° geomagnetic; each step of Kp pushes it roughly 2° toward the equator.

At 50.4° geomagnetic, Boulogne-Billancourt needs about Kp 7 for aurora low on the horizon, Kp 9 or more for a display high in the sky.

Aurora forecast for nearby cities

• Northern lights Paris 16 Passy
• Northern lights Paris 15 Vaugirard
• Northern lights Paris 14 Observatoire
• Northern lights Paris 17 Batignolles-Monceau
• Northern lights Paris
• Northern lights Paris 13 Gobelins
• Northern lights Paris 18 Buttes-Montmartre
• Northern lights Paris 11 Popincourt

More sky and weather

• Aurora forecast (all cities)
• Northern Taurids meteor shower
• Meteor showers
• Weather warnings