TonightAurora
Tonight ·

Can you see the northern lights tonight?

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Reading the sky…

Aurora chance · next 7 nights

    View the 7-night outlook for your city

    City-specific Kp forecast, cloud cover graph, and the best night of the week.

    Open 27-day outlook

    How we decide a quick tour of the 5 factors — each one scored, weighted, and shown to you

    Kp index (NOAA SWPC)

    The planetary geomagnetic index, 0–9. Your location's magnetic latitude decides the threshold: London needs Kp 7, Tromsø only needs Kp 3.

    Cloud cover (Open-Meteo)

    Hourly total cloud at your coordinates. Below ~30% is fine; above 80% usually blocks the show.

    Moon phase & illumination

    Above 70% illumination washes out all but the strongest Kp. Below 30% is essentially "extra dark".

    Darkness window

    Astronomical twilight ends when the sun is 18° below the horizon. Earlier sunset ≠ earlier aurora.

    Light pollution (Bortle)

    From our pre-computed Bortle grid. Class 4–9 cities need stronger Kp to see anything.

    Quick answers

    How accurate is this aurora forecast?

    Short-term (under 3 hours) is the most accurate. The 27-day outlook from NOAA is research-grade — useful for planning, not for promising a show.

    What does MAYBE mean?

    Part of the night will work but a single factor (cloud, moon, twilight) is hurting. Open the breakdown to see which.

    Do I need to sign up?

    No — no signup, no app install, no account, no email collection. We count anonymous visits with Google Analytics and Google AdSense serves the ads; both are spelled out on the privacy page.

    Why is my city wrong?

    We use a public IP geolocation service. If you share a corporate VPN or mobile carrier, the result can be off. Use the city picker at the top of the page to override it, or hit "Use my location".

    The northern lights, explained simply

    The aurora borealis — and its southern twin, aurora australis — appears when charged particles from the Sun (the solar wind) collide with gases in Earth's upper atmosphere. The colour depends on which gas is hit and at what altitude: green from oxygen around 100–300 km, red from oxygen above 200 km, blue and purple from nitrogen lower down.

    What you actually see depends on three things: how strong the solar wind is when it hits Earth's magnetic field, how dark your sky is, and whether clouds get in the way. We track all three in real time and combine them into the single answer above.

    The 27-day cycle

    The Sun rotates on its axis every ~27 days. Active regions (sunspots, coronal holes) often persist across one or two rotations — that's why NOAA publishes a 27-day outlook. Use it to spot windows of opportunity, not promises.

    Solar maximum (2024–2026)

    We are inside the most active period of the current ~11-year solar cycle. More sunspots means more frequent and more intense geomagnetic storms. Autumn 2026 is statistically the best viewing window for the next 12 months.

    Can't see it from home? Fly to it Aurora trip guides from 15 major cities — flight times, seasons, odds.

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