It seems to me in the winter time temperatures can be brutally cold in Chicago and be rather mild in places farther north like Billings and Rapid City. This makes no sense. I know places far north like Seattle are mild due to near the ocean but that would not have any effect on places farther inland.
Because of dryer weather is caused by the large amounts of rain shadows caused by the Cascades, Sierras and finally the Rocky Mountains. Case and point; Billings has 13.66 inches of precipitation a year and has a high/low December temperature of 35.2F/17.8F. Rapid City for comparison sake has 16.29 inches of precipitation a with a December high/low of 36.9F/13.0F. Chicago on the other hand is at 39.09 inches of precipitation a year with a December high/low of 35.3f/22.7F. So basically all three cities are roughly on par temperature wise but the main difference is that you have a crap ton of more sources for precipitation in the midwest....the Great Lakes would be one of the biggest sources. When I lived in Michigan and Chicago we would always get "lake effect" snow storms that were driven my moisture evaporating from the Great Lakes. Basically you are running into a near desert or "semi-arid" climate in the Great Plains which is driven by all those high mountain ranges that line the west coast.
Air moving over mountains cools as it is forced up by the terrain and then it warms as the air sinks down the other side of the range. Cities like Billings or Rapid City or Denver are down wind from the westerly trade winds in the middle latitudes and downhill from prominent mountain ranges so they can expect moderating influences on temperature.
Chicago and other Midwest cities are on effectively flat terrain. With no significant changes in altitude, cold air masses can push east unimpeded.
From what I remember about living in Grand Junction for a couple of months, this sounds like the same effect that makes the climate of that city more akin to that of Phoenix than Denver.
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Quote from: empirestate on July 24, 2016, 03:05:38 PM
From what I remember about living in Grand Junction for a couple of months, this sounds like the same effect that makes the climate of that city more akin to that of Phoenix than Denver.
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Yeah up there you basically have the entirety of the Colorado Plateau, The Grand Staircase, Every mountain in the Great Basin and the Sierras working against the rain directly from the west. It was always interesting to see how much rain and snow really backed up to the southern edge of the plateau in Flagstaff, Show Low and Payson...sorta just stays there.
The high plains are known to have the most volatile temperature ranges for any given day.
From the noble and infallible (/s) Wikipedia:
Quote"The largest recorded temperature change in one place over a 24-hour period occurred on January 15, 1972 in Loma, Montana, when the temperature rose from −54 to 49 °F (−47.8 to 9.4 °C). The most dramatic temperature changes occur in North American climates susceptible to Chinook winds."
Other sources I've found in the past have cited Spearfish, SD as the site of the greatest 24-hr temperature change. Chicago has volatile temperature ranges, but they aren't superlative like the Billings/Rapid City region.