Weather Whys: Gray sky, blue sky (2024)

FAQs

Weather Whys: Gray sky, blue sky? ›

Haze and dust in the atmosphere can cause them to appear yellow, orange, or red. As clouds thicken, sunlight passing through them will diminish or be blocked, giving the cloud a gray color. If there is no direct sunlight striking the cloud, it may even reflect the color of the sky and appear bluish.

Without light from the sun creating Rayleigh scattering, the sky cannot be seen as blue, except in certain conditions when the moon is up. Clouds can obscure the color of the sky. With cloudy weather overhead, the sky can be whitish, grey, or even black.

A: On hazy days, large particles in the air make the sky appear gray or even white, McRoberts explains. "These larger particles tend to scatter more wavelengths of light in the color spectrum," he says. "Hazy air has a lot of water molecules, and these molecules can scatter light of all wavelengths, not just blue.

An inversion is a warm layer of air above the ground. It can form under cool, clear nights with little wind. Inversions can cause, gray, gloomy skies.

A common Spring scenario

The warmer air resists mixing with the cooler air below it, acting as a sort of blanket, or what's known as a temperature inversion. That not only keeps the low level clouds around, but often keeps pollution from escaping, leading to all sorts of air quality issues.

This is because the color that you see is dependent upon the color of the light you are using. People's color perceptions can easily be fooled by minor changes in the source light. It could be that you have a mild form of colorblindness that throws the gray out of balance.

As the size and concentration of the hydrometeors increases, less and less sunlight penetrates the cloud, resulting in multiple scattering. We perceive these clouds as dark clouds in varying shades of grey.

More commonly, the contrast between the background (blue sky or additional clouds) and the foreground cloud overwhelms our vision. In essence, the overwhelming brightness of the background tricks our eyes into perceiving the relatively darker foreground clouds as gray.

Haze often occurs when suspended dust and smoke particles accumulate in relatively dry air. When weather conditions block the dispersal of smoke and other pollutants they concentrate and form a usually low-hanging shroud that impairs visibility and may become a respiratory health threat if excessively inhaled.

Light pollution is visible in several directions. Under these skies, the sky background begins to appear gray instead of black. You can see the Milky Way, but the fine detail is gone. Some clouds are illuminated in the direction of light sources, but overhead clouds remain dark.

Do grey skies mean rain? ›

A thick, gray overcast sky often means that rain is on the way. These clouds are called cumulonimbus clouds, which can produce heavy rain, thunder, and lightning. It's important to stay indoors during these types of storms and avoid standing under trees or other tall objects.

A day that's gray and cloudy is overcast, and a dull, sunless sky can also be described this way.

But on humid days the amount of aerosols can be greater, and these cause scattering of light that makes for haze which appears gray. Water vapor is a transparent and colorless, and invisible gas in our atmosphere. Water vapor in the sky condenses into mist, clouds, and fog (aerosol) below the dew point.

Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time. Closer to the horizon, the sky fades to a lighter blue or white.

When the sun is shining, the blue wavelengths of light are scattered more easily, making the sky appear blue. However, on a cloudy or overcast day, the water droplets and particles in the atmosphere scatter all wavelengths of light equally, giving the sky a grey appearance.

It's a phenomenon that occurs most often during the late spring to early summer months and generally in the overnight to morning hours. If the conditions are just right, overcast skies can last into the afternoon and sometimes even for a few days.

"grey skies" is an idiom, though I can't find a proper reference for it. It's used in poems and songs, meaning "life's troubles". So yes, if sky was in the singular, it would mean the literal sky; the weather began to clear. skies in this context is not totally clear. (HA!

Shades of blue: The blueness of the sky is affected by many factors, including moisture and particulate matter in the air. Light that comes from the Sun passes through the Earth's atmosphere which mainly consists of nitrogen and oxygen atoms. Visible light from the sun is actually made up of a rainbow of colours.

The water molecules are thickly packed but spread apart evenly enough to cover the sky so much that they can even block out some sunlight. What a bummer! Stratus clouds can make the sky grey all day.