On April 29, Denver neared its record high for the date when it hit 80 degrees. By the next night, temperatures dove to 38 degrees. A snowstorm dumped 3.2 inches on the city through May 1.
This was not the first extreme jump for Denver this spring. April 7 and 8 brought temperatures in the 70s and 80s before plunging to 22 degrees and receiving almost a foot of snow. Temperatures then warmed into the 60s before more cold and an additional 7 inches of snow moved through for April 15 to the 17. More warm air settled into the city again, before 4 inches of snow accumulated on April 22 and 23.
Snow falls across Denver on May 1, 2013. AP Photo/Ed Andrieski
Denver's location makes it no stranger to weather extremes.
"Springtime can be very volatile on the Front Range of the Rockies," said AccuWeather.com meteorologist Ken Clark.
Clark explained that westerly flows off the Rockies create warmth, but quick-moving cold fronts are able to send temperatures into a dive. Cold fronts from Canada are pushed off the east side of the Rockies and drain into the Denver area.
These drastic swings are common for Denver. Clark said that they will typically get the most snow in the late fall and early winter, then again in mid-spring rather than in the traditionally main winter months. However, despite the usual variations in weather, this year has been more extreme than most.
"It's been about 6.5 degrees below normal since April 1," Clark said. "Some days have been 20 degrees above average, but many others have been 20 degrees below average."
Low temperature records have been set this year on April 9, 10, 16, 22 and May 2. Clark cites an active storm track as the force behind the extremes. Moisture from the southeast is pulled into cold air coming down from Canada, creating conditions for snow.
It's not only snow and cold that Denver needs to look out for. Summer thunderstorms are also very common, and the area has high occurrences of hail.
Dry and sunny conditions will continue in San Francisco for the the official start to winter and the Christmas holiday.
Sunshine will return in full force for the weekend, the official start to winter, and Christmas in Los Angeles.
Big changes are on the way for parts of the Western and Central states late this week and into this weekend.
Similar to the days prior to Thanksgiving, the worst weather will focus on the days prior to Christmas as millions of travelers take to the roads and skies in the U.S. and southern Canada.
Warm air is forecast to surge into much of the eastern half of the nation by the weekend and will be accompanied by heavy rain and flooding risk in some locations.
Thunderstorms in parts of the South this weekend may become strong enough to threaten lives and property.
Lancaster, CA (1984)
Ended up with about a foot of snow. One spot in Kern County (North of LA) had 19" of snow.
Valley Forge, PA (1777)
Continental Army encamped at Valley Forge on a day having "stormy winds and piecing cold" in-and-out winter followed.
Arctic blast causes temperatures to plunge to 20 to 30 below zero.