Biocast-Bioluminescence Alerts Downloads & RevenueBiocast-Bioluminescence Alerts · App Store

Biocast forecasts marine bioluminescence, the natural glow (also called sea sparkle) that lights up the water on some nights, at coastal locations around New Zealand. It shows you which beaches are worth a look tonight, and can alert you when conditions line up.

How it works
Each location gets a likelihood score from a model that weighs dozens of ocean and weather variables: phytoplankton and chlorophyll, sea surface temperature and its anomalies, recent sunlight, nitrate, dissolved oxygen and pH, days since the last rainfall and the runoff behind it, plus the wind, swell, tide and chop that decide whether you will actually see anything on the night. Live sightings from visitors run alongside the forecast, and recent confirmed sightings carry the most weight.

What you get
- A nightly likelihood rating for each beach, from Very Low to Very High
- The best hour of the evening to look, where there is enough data
- An hour-by-hour breakdown of the conditions behind the score
- An interactive map and a sortable list of beaches
- Community sightings: report what you see, and check recent reports from others
- Alerts by email or push when your chosen beaches and levels look promising

Bioluminescence is unpredictable, and a rating is a likelihood, not a guarantee. Some nights are a coin flip even at Very High. The project is in its early days, and the forecasts sharpen over time as more sightings come in, including the nights nobody saw anything, which matter to the model just as much.

Biocast is a free project focused on New Zealand, built on public data from MetService, NIWA, Earth Sciences New Zealand, Copernicus, NOAA and Open-Meteo.

Stay safe out there: check the tide times, bring a torch, watch your footing, and never go to the water's edge alone at night. Enjoy the glow from the shore.