Webcams seem very cloudy (Denver, Colorado Springs: how much, live in, bill)

[lurtsman]

I've watched 25 or so days on the webcam archives from around the city and I've been surprised by the amount of cloud cover. I didn't believe the 300 days of sunshine line, but I did expect to see mostly clear skies. I've seen more days with large amounts of clouds rolling through than days with very few to none.

What's the cloud situation really like?

Does anyone else find themselves vastly less trusting of any company that tries to use the "300" statement as a fact?

[Bullitt007]

From the Colorado Climate Center:


How much sunshine do we get in Colorado? On average for a year, how many days does the sun shine in Colorado?

This is a question that comes up several times per year. You will find in many Chamber of Commerce publications from all areas of Colorado that we get at least 300 days of sunshine each year. The only problem is, there is no official definition of "days of sunshine" so there is no data set that you can easily turn to.
Have you ever wondered if anyone actually keeps track of stuff like this? It turns out that for many years, three locations in Colorado have operated an instrument called a "sunshine switch" -- Pueblo, Denver and Colorado Springs. If this instrument is cleaned and perfectly calibrated (which it rarely is), it can tell you minute by minute each day when the sun was shining. We did a study over 10 years ago based on these three stations and found that for Denver if you count every day when the sun came out for at least one hour, that then you could come up with an average of around 300 "days of sunshine" each year.
But my assumption is that most people, if they heard "day of sunshine" would assume that meant it was a sunny day. The National Weather Service did establish a criterion for determining clear, cloudy and partly cloudy days based on sky cover. Any day, with an average skycover of 30% or less was considered a clear day, while if the sky cover was 80% or more, (averaged from hourly sky condition reports between sunrise and sunset), it was considered a cloudy day. Anything in between counts as "partly cloudy". Based on this definition, there are 115 clear days, 130 partly cloudy ones and 120 cloudy days, on average, each year. Over in Grand Junction the number of clear days is great (137) but the number of cloudy days is almost the same (121).
But the fact is, here in Colorado and much of the Rocky Mountain region, there are relatively few totally clear days but a whole lot of days when the sun peeks out at least a little. Therefore, we tend to brag about our sunshine -- but mislead folks along the way.
I am circling around your questions. Of course the answer will differ from one location to another in Colorado with the most sunshine occurring down around Alamosa with the least around Boulder and in the northern mountains of the state. -- In the Denver area there are probably only 30-40 totally overcast days per year, and some of them are even fairly bright -- about 300 days would have at least one hour of sunshine sometime during the day, but only about 115 days per year fit the classic definition of "clear".

[lurtsman]

Thank you. That was remarkably informative. I wouldn't have considered one hour of sunshine to equate to a "day of sunshine" anymore than I consider one hour of work to be equal to "one day of work". I think private companies advertising that way would risk serious fines and having people dispute charges. I'm not sure if I find it more disheartening that there are only 115 clear days, or that the local boards find it acceptable to misrepresent the data. 80% cloud is being referred to as a "day of sunshine". I think I should work for one of those places and bill them for a day after working for a single hour, and give them a nasty court case if they try to fire me. I would consider 80% clear to be a "day of sunshine".

[hollyt00]

Today was fairly cloudy in the morning, yesterday was very cloudy with lots of peeks of sunshine.

Rarely do we get days of seemingly unending days of cloudiness. If it is more than three days in a row of clouds, people start snapping at each other, as we are used to seeing the sun for at least a portion of the day. And I'd, in my entirely unprofessional opinion, would put that portion at being a good half the day.

[KaaBoom]

Originally Posted by lurtsman

I've watched 25 or so days on the webcam archives from around the city and I've been surprised by the amount of cloud cover. I didn't believe the 300 days of sunshine line, but I did expect to see mostly clear skies. I've seen more days with large amounts of clouds rolling through than days with very few to none.

What's the cloud situation really like?

Does anyone else find themselves vastly less trusting of any company that tries to use the "300" statement as a fact?

300 days of sunshine simply means that the sun is visible at some point in the day, 300 days a year. Some of those days could have as little as one min. of sunshine.

It also means that there are 65 days (two months) out of the year when the sun will not be visible at all.

300 days of sunshine is really nothing to brag about. IMHO, Colorado winters are pretty depressing. Even if it is sunny, it's kind of hard to enjoy it, if the temperature is hovering around zero.

[lalahartma]

Originally Posted by hollyt00

Today was fairly cloudy in the morning, yesterday was very cloudy with lots of peeks of sunshine.

Rarely do we get days of seemingly unending days of cloudiness. If it is more than three days in a row of clouds, people start snapping at each other, as we are used to seeing the sun for at least a portion of the day. And I'd, in my entirely unprofessional opinion, would put that portion at being a good half the day.

Well said. It is does seem that one gets spoiled and even a bit of sun during the day helps!

We are entering our snowy time...hopefully we'll get some!

[lurtsman]

Is there a way to check this statistic for other areas? I suspect by these definitions that Iowa is getting vastly more sunny days. I'd think we only had full cloud cover here 25 days or so per year, but I could be wrong.

[GoneNative]

The Chamber of Commerce tends to exaggerate, as it happens. But it is still one of the sunniest places you'll live in. And the cloud cover helps keep summer temperatures down, so it's actually a good thing.

[lalahartma]

Originally Posted by lurtsman

Is there a way to check this statistic for other areas? I suspect by these definitions that Iowa is getting vastly more sunny days. I'd think we only had full cloud cover here 25 days or so per year, but I could be wrong.

Let me google that for you

[lurtsman]

I'm very ashamed that the top results held the answer


This is one of the most pathetic moments of my life.