About Aurora Forecast

Aurora Forecast (tonightaurora.com) answers one question — "can I see the aurora from where I am tonight?" — in the fewest possible seconds. Every city page computes a live, weighted answer from primary scientific data sources, states its reasoning in plain language, and stays honest when the answer is probably not. It is built and operated by an independent developer with a background in product engineering, assisted by amateur astronomers who stress-test the verdicts against what they actually see in the sky.

Why we built this

Most aurora apps do too much and answer too little. They show you a heatmap, a Kp graph, a cloud chart, a moon widget, a notification bell, and a "subscribe for $4.99" button. The thing they don't do is tell you whether to bother going outside tonight.

We started Aurora Forecast because people we knew were tired of opening four apps and still guessing — and tired of forecasts that inflated optimism to keep them engaged. The difference here is a single weighted score and a one-word answer (GO / MAYBE / LOW / NO) backed by a transparent five-factor breakdown: Kp vs your city's threshold, night-average cloud cover, moon illumination, the astronomical darkness window, and light pollution. Every factor card shows its number and its weight, so when the verdict is MAYBE you can see exactly which factor is holding the night back.

What we will not do

• Sell an account, tier, or feature behind a paywall.
• Send push notifications — web push apps get uninstalled for noise, and we keep no relationship to sell.
• Track you. No accounts, no cookies, no cross-site identifiers; the forecasts compute in your browser.
• Publish a "definitive" 14-day aurora forecast — that would be snake oil, and NOAA's own guidance agrees.
• Show a false GO to keep you coming back. A LOW night is labelled LOW.

Where the data comes from

Every number on this site is sourced from a primary science agency or an open data feed, computed client-side the moment you open a page:

• NOAA Space Weather Prediction Center — the 3-hourly Kp forecast, the observed Kp feed, and the 27-day Space Weather Outlook.
• Open-Meteo — hourly cloud cover for each city's exact coordinates (free public API, no key required).
• Standard astronomical algorithms — sun altitude (for the darkness window) and lunar illumination, computed locally in your browser.
• Public light-pollution data — a pre-processed Bortle class per city.

The full weighting logic, hard rules and known limitations are documented on the methodology page — deliberately, so that anyone can check our work or reproduce it.

Editorial standards

City guides, trip pages and explainer articles are written by us, fact-checked against the same primary sources, and reviewed on a schedule: thresholds and city data are re-validated each season, articles are updated when the underlying science or data feeds change, and corrections submitted by readers are applied with attribution to the source. When we don't know something — substorm timing, for example, which no public feed provides at minute resolution — the pages say so instead of guessing.

Limitations, honestly stated

We do not account for: substorm onset at minute resolution (no public source exists), local weather effects finer than the cloud model's resolution — inversions and sea fog can flip conditions in 30 minutes — or CME impacts whose arrival time is still uncertain while en route. The MAYBE and LOW labels exist precisely because of these gaps. Cloud forecasts degrade quickly beyond 48 hours, and the 27-day outlook is a planning window, not a promise. If a verdict on this site was wrong for your sky last night, tell us — verdict misses feed directly into threshold tuning.

Contact

Everything routes through one address — [email protected] — answered by a human within five working days.