Kp — for your latitude
We work out the Kp you need from your geomagnetic latitude — the distance from the magnetic pole, not the geographic one. Yorkshire ≈ 5. London ≈ 6.4. Calgary ≈ 4.3, despite sitting level with London on a map.
The problem
Kp alone is why you've missed every display over your own house
The Kp index measures how disturbed Earth's magnetic field is — globally. It doesn't know your sky is overcast, that it's 3pm, or that your postcode needs Kp 6 while the app's default fires at 4. That's why aurora apps cry wolf, why you stopped opening them, and why the one night it was visible from your street, you found out from Facebook the next morning.
Gate 01
Gate 02
Cloud — per hour, forecast
Not "current conditions". An hour-by-hour cloud forecast for your exact coordinates, so a clearing at 1am counts and a clouded-over midnight doesn't.
Gate 03
Darkness — obviously
No alerts in daylight or twilight. Dusk and dawn for your spot, every hour scored against them. It sounds basic. Most apps still get it wrong.
Gate 04
Your rules, if you want them
Alert on our overall chance, or flip one switch and set your own limits — minimum Kp, maximum cloud, solar wind — and we alert only when every one is met. Your thresholds, not our black box.
How it works
Three steps, no install, no account
Open it in your browser
AurorAlert is a progressive web app. No app store, no download, works on any phone or laptop tonight. Add it to your home screen if you like it.
Set your spot
Use your device location, or type any coordinates — your garden, a dark-sky site up the road, the cabin you've booked in Tromsø. Saved locations stay put.
Wait for the nudge
Most nights, nothing happens. That's the product working. When your hours light up green, go outside — the sky's already been checked.
Why "honest"? Because the formula is published — every threshold, every multiplier, on one page — and because a forecast app that pings you nightly isn't forecasting, it's marketing. Ours mostly says no. When it says yes, it means it.
Timing
No, you haven't missed it
Solar Cycle 25 peaked in October 2024 — but the record shows the biggest individual storms tend to arrive in the years after the peak. The Halloween 2003 superstorms came two years past maximum; the strongest flares of the previous cycle came three years after its. The declining phase we're in now runs hot through 2027, with long-lived coronal holes adding regular, repeatable storm windows. The displays that reach Yorkshire, Manchester and beyond are still coming. The only question is whether you'll know in time.
Questions
Straight answers
Can I see the northern lights tonight?
Only if four things line up at your location: Kp high enough for your geomagnetic latitude, darkness, low cloud, and a clear view north. AurorAlert checks all four for your exact spot, hour by hour — the Tonight guide shows you how to read the answer.
Why do aurora apps send so many false alerts?
Because most alert on Kp alone, and Kp says nothing about your cloud, your daylight, or your latitude. A Kp 5 ping under full cloud is noise. We gate every alert on all four conditions — so most nights we stay quiet, deliberately.
What Kp do I need where I live?
It depends on your geomagnetic latitude. Roughly: northern Scotland Kp 4–5, Yorkshire Kp 5, London Kp 6–7, Iceland and Tromsø Kp 1–2. The app calculates your exact number and shows it — no guessing.
Does it work for the aurora australis?
Yes — the maths uses distance from the magnetic pole, so the southern hemisphere works identically. Tasmania and New Zealand's South Island are the best-placed spots.
What does it cost, and what data do you take?
It's free, browser-based and ad-free. The only permission is location — and you can type coordinates instead of granting it. We don't want your contacts, your camera or your calendar, and we never ask.
Be on the list when the sky goes green
One email at launch. Then silence, until the silence is the point.