October skies darker than December skies?

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Discussion Overview

The discussion centers around the perceived differences in the color of night skies between October and December, particularly in the Northern Hemisphere at middle latitudes. Participants explore various hypotheses regarding atmospheric conditions, weather patterns, and other factors that may influence these observations.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that October skies appear darker, while December skies seem bluer, suggesting this may be a personal observation rather than a universal experience.
  • Another participant points out that October is often cloudier due to active weather systems, which may contribute to a dull appearance, contrasting with clearer December skies.
  • A later reply clarifies that the discussion is specifically about night skies, acknowledging the relevance of this detail to the hypotheses presented.
  • Questions are raised about the directional perception of sky color and the potential influence of snow, the Northern Lights, and phenomena like Gegenschein and Zodiacal light on the night sky's appearance.
  • One participant challenges the notion of blue night skies, questioning the role of Rayleigh scattering and whether such perceptions are subjective or vary by location.

Areas of Agreement / Disagreement

Participants express differing views on the color of night skies in October versus December, with no consensus reached on the reasons behind these observations or the validity of the claims made.

Contextual Notes

Some hypotheses depend on specific atmospheric conditions, such as cloud cover and weather patterns, which may vary significantly by location and time. The discussion also touches on the influence of natural phenomena that could affect sky brightness and color perception.

DaveC426913
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October skies always seem to be very black, whereas December skies seem blue. I don;t know if anyone else has observed this, or whether it's just my imagination.

I have some hypotheses, but none of them seem satisfactory.

- Daylight savings ends in late October. So Oct/Nov skies really are darker than Sept. (but that doesn't explain lighter skies in December)
- It is often rainy in autumn, so the roads reflect vehicle and street lights. And there's (sometimes) snow on the ground in December (though not around here in recent memory).
- Moon is typically in a different phase for a given time of night? (Don't know)
 
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We are talking Northern hemisphere of course, and at middle-ish latitudes, but in many parts October is often cloudier than December with more active weather systems around.
So although October days are longer they are frequently dull due to lots of cloud, (I wouldn't quite compare that dullness with black though).
Typically in December there are less active weather systems, so less cloudy days, and there can be extended periods of slow moving high pressure systems leading to calm and cloud free skies.
 
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To my horror, I do not seem to have actually specified that I am referring to night skies.

Thanks. That actually a pretty plausible hypothesis.
 
Is there any directivity that you have noticed - darker/lighter to the south, north east, west.
Thinking that with the snow on the ground, the Northern Lights, even if you do not see them directly, may reflect back up into the sky.

Also, what about the Gegenschein,
https://en.wikipedia.org/wiki/Gegenschein

Or the Zodiacal light,
https://en.wikipedia.org/wiki/Zodiacal_light

Both due to dust, and since December has you tilted more inline with the solar plane...

There is also Airglow, to brighten up the night sky,
https://en.wikipedia.org/wiki/Airglow

Frankly, how seasonal would any of those be?
 
Whoa! Dave. Your eyes must be a lot different than mine. I don't recall ever (and I'm as old as dirt) seeing blue night-time skies in any month. Blue skies are caused by Rayleigh scattering of sunlight--right? There is no sunlight at night--right? Where does the blue come from? Is it subjective?

I wonder if you would see the same monthly difference if you live somewhere else?
 

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