Heliocast: Aurora Forecast

Will you see the aurora tonight? Heliocast answers the moment you open it, in a sentence, for exactly where you are standing.

Most aurora apps hand you a Kp number and leave the hard part to you. But a Kp 6 is worth nothing under cloud, worth nothing under a full moon, and worth nothing at 9pm in June. Heliocast checks all four at once - geomagnetic activity, darkness, moonlight and your local cloud - and gives you one verdict with the reason attached. When the answer is no, it names which of the four is stopping you.

TONIGHT, ANSWERED
- A plain-language verdict and a 0-100 visibility score for your coordinates
- Tonight's astronomical dark window, and how long it lasts
- Moon phase, cloud cover by layer, live Kp and Bz
- Where the auroral oval is sitting right now

WHICH NIGHT TO GO
- Every night ahead ranked on darkness, moon, cloud and the NOAA forecast
- An hour-by-hour grid, 6pm to 6am, for the next three nights
- Save the place you are traveling to and plan against its sky, not yours

ALERTS THAT KNOW YOUR SKY
- Our server watches NOAA's 1-minute feed all night and wakes your phone the
moment your threshold is crossed, with the app closed
- Cloud-aware and dark-aware by default, so a storm you could never have seen
does not ring at 3am
- Thresholds on Kp, and with Pro on Bz, solar wind speed and visibility

A 3D AURORA MAP
- Spin a live globe carrying the OVATION auroral oval and the day/night line
- Six Arctic observatories and their all-sky cameras, one tap away:
Yellowknife, Churchill, Fairbanks, Sodankyla, Tromso and Kiruna

THE SUN, IN FULL
- NASA SDO in eight wavelengths, plus white-light continuum and magnetogram
- Active regions plotted at their real heliographic positions
- SOHO/LASCO C2 and C3 coronagraphs, and GOES CCOR-1
- L1 solar wind speed, density and the full interplanetary magnetic field
- GOES X-ray and proton flux with flare classes, for anyone watching HF
propagation and radio blackouts

WHAT IS HEADING THIS WAY
- Earth-directed CMEs with predicted arrival times and expected Kp
- Flare history, live NOAA watches and warnings, and the R, S and G scales

Plus a sightings journal that files the conditions alongside your photo, so you
learn what actually works, and a Learn section that explains every number in the app.

WIDGETS
Tonight's verdict on your home screen and your lock screen.

EIGHT AUTHORITATIVE FEEDS
NOAA SWPC, NASA SDO, NASA DONKI, SOHO/LASCO, GOES, DSCOVR, Kyoto WDC and USGS, and MET Norway for cloud. Everything is fetched and cached on our own server, so the app stays fast and the agencies never see anything about you.

FREE, AND HONEST ABOUT IT
No account. No ads. No sign-up wall. The free tier is a real app: tonight's
verdict, the full 3D map, live Kp, the Sun and solar wind, the observatories,
the journal, and one overnight alert.

HELIOCAST PRO
- The full 14-night ranking, not just three
- Up to 10 saved places, home and the trip
- Unlimited alerts on Bz, wind speed and visibility, plus quiet hours
- A weather-radar layer on the globe
- Your full sightings archive, kept with its conditions

Recent changes:
We improved app performance and notifications.