october skyAfter asking this question some time ago, it seems the answer is ‘yes’.

Evidently, there are two things at work here:

1) When the sun is lower on the horizon, which it is during the fall and winter, more of the scattered light is directed towards the observer’s eyes, which increases the amount of blue in the sky.

2) In the fall the air has lower humidity, which reduces scattering due to water vapor. The scattering due to water vapor would otherwise wash out the blue color.

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