Bowcast

Rainbow forecast for Victoria

Victoria, British Columbia, Canada: today's peak estimated rainbow chance, the best forecast interval to look up, and the week ahead.

Checking about 40 forecast ensemble members for sunlit rain near Victoria…

Open the live map for Victoria

Rainbow weather in Victoria

Victoria gets its rainbows from Pacific storm-light: frontal systems that break into showers as they cross the coast, with sharp clearings behind them. The hour after a front passes, when the western sky opens while rain still hangs to the east, is the classic setup here.

At 48.4° north, Victoria's useful viewing window shifts with the seasons. Local winter brings longer periods of low sun, while summer usually concentrates the geometry near sunrise and sunset.

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 Victoria.

Rainbow questions, answered

When do rainbows appear in Victoria?
Rainbows need sunlit rain with the sun lower than about 42 degrees, so in Victoria 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 Victoria?
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 Victoria today?
Bowcast checks about 40 forecast ensemble members for sunlit-rain ingredients around Victoria, 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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