It's easy to see why Mother Nature Network is based in Atlanta. Other than this past winter, the city has great weather: about 62 days a year fall within what could be called "pleasant," well above the national average.

How do we know this? The data comes from a great new web-app called The Pleasant Places to Live, created by Atlanta-based programmer Kelly Norton, a former Google engineer who now works for the craft site Etsy. The app uses 23 years of weather data collected by the National Oceanic and Atmospheric Administration (NOAA) and presents it as an artistic map of blue circles. The darker the circle, the more pleasant the city.

Of course everyone has different definitions of what makes a day "pleasant," but Norton told Business Insider that he defined it as a mean daily temperature between 55 degrees and 75 degrees. On top of that, the maximum daily temperature in his "pleasant cities" doesn't dip below 45 degrees and never goes above 85. He also used precipitation (both rain and snow) in his calculations: if a day had more than .010 inches of rain or .1 inches of snow, it wasn't pleasant. (No kidding.)

The online map is really easy to use. You can either mouse over a given city or type in a ZIP code to zoom in. For instance, my region of Maine only has (sigh) 54 pleasant days a year, all clustered from May to October. (Atlanta, by comparison, has pleasant days from March to June and again from September to November.)

The map has some interesting revelations. The top five most pleasant places are all in California, with Los Angeles leading the list at 183 days per year. (Obviously Norton didn't factor traffic into the equation.) But California also had one of the worst places: just east of Cedarville, which only has 16 pleasant days per year. Cedarville has an elevation of more than 4,600 feet above sea level and only had about 500 residents, according to the last census. I guess now we know why.

Other sites in the "least pleasant" list: Douglas, Wyo.; northeast of Reno, Nev.; and two cities in Montana.

As Norton explains on his site, the idea for this map came up while he was traveling recently and experienced the wicked winter weather. "Whichever way I went," he wrote, "bitter cold greeted me at the end of the jet way and often with a coating of slick ice.... It got me wondering, though, where in the U.S. do you go if you want the most 'pleasant' days in a year?"

I don't know about you, but I think a trip to a dark blue circle is in my future.

Related on MNN: