Rainbow forecast for Reykjavík
Reykjavík, Iceland: today's peak estimated rainbow chance, the best forecast interval to look up, and the week ahead.
Rainbow weather in Reykjavík
Reykjavík is a mid-ocean island climate: volcanic terrain squeezes showers out of clean maritime air, and the surrounding sea keeps them small and fast-moving. Clean air makes for unusually vivid colors when a bow appears.
At 64.2° north, Reykjavík's rainbow geometry changes strongly with the seasons. Summer favors early and late hours; the lower winter sun can keep the geometry open longer, although daylight is shorter.
Wherever you are, the geometry is the same: a primary rainbow forms opposite the sun while the sun is less than about 42 degrees above the horizon. Bowcast's research-informed heuristics give extra weight to clearing showers. The gauge above applies them to ensemble forecasts for the 12 km around Reykjavík.
Rainbow questions, answered
- When do rainbows appear in Reykjavík?
- Rainbows need sunlit rain with the sun lower than about 42 degrees, so in Reykjavík useful windows often occur after sunrise or before sunset on showery days. A study in ZhaoSu, China found that about nine in ten observed rainbows occurred during the hour after rainfall. Bowcast uses that regional finding as research guidance, not a universal rate.
- Where should I look for a rainbow in Reykjavík?
- Always directly opposite the sun: put the sun at your back and look toward the retreating rain. In the evening that means looking east; in the morning, west.
- What is the estimated rainbow chance in Reykjavík today?
- Bowcast checks about 40 forecast ensemble members for sunlit-rain ingredients around Reykjavík, hour by hour, for the next 7 days. The result is an estimated chance from model agreement, not a probability calibrated against observed rainbow frequencies. This page shows today's peak and best forecast interval; the Now board shows the interval containing the current time.
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