Rainbows appear higher in the sky when the sun is lower in the sky.
Here's a breakdown of why this happens:
-
Rainbow Formation: Rainbows are formed by sunlight refracting (bending) and reflecting within raindrops. The angle between the incoming sunlight, the raindrop, and the light reaching your eye is approximately 42 degrees.
-
The Rainbow's Position: The center of the rainbow is always directly opposite the sun from your perspective. Imagine a line connecting the sun, your head, and extending out to the sky. The rainbow will form around that line, with its center on that line.
-
Sun's Elevation and Rainbow Height:
- Low Sun = High Rainbow: When the sun is low on the horizon (like during sunrise or sunset), the center of the rainbow is higher in the sky. Because the rainbow is a circle (or arc), this results in a larger, higher arc being visible. Think of it as seeing more of the rainbow "above" the horizon.
- High Sun = Low (or No) Rainbow: Conversely, when the sun is high in the sky, the center of the rainbow is lower, potentially even below the horizon. If the sun's elevation is greater than 42 degrees, the rainbow's arc will be entirely below the horizon, and you won't see it from the ground.
-
Practical Implications: This explains why you're more likely to see a full, high rainbow shortly after sunrise or just before sunset. During midday, when the sun is high, rainbows are less common and, if visible, will appear much lower and smaller.
In essence, the sun's position dictates the rainbow's position. A lower sun creates a higher rainbow.
