Bowcast: Rainbow Forecast

Know when to look, and which way to face for a rainbow. A rainbow needs two things in the same sky at the same time: low sunlight, and falling rain. Bowcast works out when those two line up near you. Open it and the answer comes first. A chance for right now, the direction to face, and the window to watch. Everything underneath is there if you want it. • Your own sky, and the sky 12km in every direction around you, so you can see which way the better chance lies. • A live worldwide board, ranked, for when you want to know where it is happening on Earth right now • Seven days ahead, and interval by interval for today • Which way to face, worked out from the position of the sun • Optional alerts at a threshold you choose, anywhere from 5% to 95% • Your last reading stays readable with no connection, labeled saved, offline or stale, rather than going blank • Optional Seen or Not seen reports, no account, which is how a forecast like this gets calibrated • Share a sighting card to Instagram Stories or the iOS share sheet Estimated chance is the share of about forty ensemble forecast members that produced sunlit rain. It is not yet calibrated against observed rainbows, and it is labeled an estimate for exactly that reason. When ensemble data is unavailable you get a Conditions score /100 instead. It ranks how favorable conditions look. It is not a percentage. The viewing direction is geometry, not chance. It never raises the number. No account, ever. Location is only requested if you tap to use it, and you can name any place in the world instead and never grant it at all. Optional reports use coordinates rounded to two decimal places.