Meteorological events that happened on December 20th:

1836
A cold wave accompanied by 70 mph winds dropped temperatures from the 40's to near 0° in matter of hours on the Illinois frontier. Many settlers froze to death. Folklore tells of chickens frozen in their tracks and men frozen to saddles, while the streams reportedly froze with ice from six inches to a foot in a few hours.

1942
An early cold wave struck areas from the Great Lakes, Mid-Atlantic to New England. Syracuse, NY set a December record low with -26°.

Locations reporting daily record lows included: Burlington, VT: -23°, Albany, NY: -17°, Milton, MA: -16°, Concord, NH: -16°, Rochester, NY: -16°, Worcester, MA: -15°, Portland, ME: -15°, Alpena, MI: -15°, Ste. St. Marie, MI: -14°, Mt. Pocono, PA: -12°, Boston, MA: -11°: Tied, Hartford, CT: -10°, Providence, RI: -10°, Avoca, PA: -10° (broke previous record by 10 degrees), Elkins, WV: -8°, Buffalo, NY: -7°, New York (Central Park), NY: -4°, Nantucket, MA: -3°, Grand Rapids, MI: -2°, Allentown, PA: -2°, Charleston, WV: -2°, Newark, NJ: -1°, Trenton, NJ: -1°, Reading, PA: 0°, Detroit, MI: 0°-Tied, Philadelphia, PA: 1°-Tied, Wilmington, DE: 2°, Richmond, VA: 2° (broke previous record by 10 degrees), Harrisburg, PA: 3°, Erie, PA: 4°, Baltimore, MD: 6° and Norfolk, VA: 16°.

1977
A "Once in a Lifetime" wind and dust storm struck the south end of the San Joaquin Valley in California. Winds reached 88 mph at Arvin before the anemometer broke and gusts were estimated at 192 mph at Arvin by a U.S. Geological Survey. Meadows Field in Bakersfield recorded sustained 46 mph winds with a gust of 63 mph. The strong winds generated a wall of dust resembling a tidal wave that was 5,000 feet high over Arvin.

Blowing sand stripped painted surfaces to bare metal and trapped people in vehicles for several hours. 70% of homes received structural damage in Arvin, Edison and East Bakersfield. 120,000 Kern County customers lost power. Agriculture was impacted as 25 million tons of soil was loosened from grazing lands. Five people died and damages totaled $34 million dollars.

Very strong Santa Ana winds gusted to 90 mph in the mountains of San Diego County. Some brush fires were fanned. Widespread crop damage was suffered in northern San Diego County to avocados, strawberries, etc. Numerous trees and power poles were knocked down. In Ramona entire barns were destroyed. Two people lost their lives.

1978
The temperature in Sioux Falls, SD never made it up to 32°. While that in itself is not unusual, the fact that Sioux Falls didn't reach 32° again until 2/21/1979 is unusual, a period of 60 straight days.

1983
An extreme bitterly cold air mass continued across much of the U.S. The temperature remained below zero at Denver, CO for 115 consecutive hours; their longest sub-zero period on record.

Locations reporting record low temperatures for the date included: International Falls, MN: -40°, Bozeman, MT: -36°, St. Cloud, MN: -35°, Duluth, MN: -34°, Casper, WY: -32°, Marquette, MI: -28°, Rochester, MN: -26°, Great Falls, MT: -25°, Cheyenne, WY: -25°, La Crosse, WI: -24°, Scottsbluff, NE: -23°: Tied, Waterloo, IA: -20°, Rapid City, SD: -20°, Omaha, NE: -18°, Kansas City, MO: -17° (broke previous record by 10 degrees), Denver, CO: -16°, Topeka, KS: -16°, Dubuque, IA: -14°: Tied, Colorado Springs, CO: -13°, Pocatello, ID: -12°, Concordia, KS: -12°, Muskegon, MI: -8°, Wichita, KS: -7°, Buffalo, NY: -7°: Tied, Boise, ID: -6°, Spokane, WA: -6°, Grand Rapids, MI: -3°, Lewiston, ID: 0°, New York (Kennedy Airport), NY: 16°-Tied and Astoria, OR: 22°-Tied.

1984
Lili, a rare December hurricane, was officially declared a tropical system in the central Atlantic as a well-defined eye type feature was apparent on satellite imagery. The hurricane peaked at sustained 80 mph winds and a pressure of 980 millibars or 28.94 inHg, very respectable for a December hurricane.

1986
An "Alberta Clipper" developed explosively just south of New England and blasted the region with high winds, torrential rain, and heavy snow. Up to 4 inches of rain fell across southern New England and winds frequently gusted to 60 and 70 mph. 30 inches of snow fell in southern Vermont, 24 inches in the higher elevations of western Massachusetts, and 20 inches in parts of New Hampshire.

1988
Strong southerly winds ahead of a cold front in the central U.S. gusted to 70 mph at Indianapolis, IN. The high winds toppled a masonry wall killing a construction worker.

Low pressure and a trailing cold front brought rain and snow and high winds to the western U.S. Winds gusted to 90 mph at the Callahan Ranch south of Reno, NV. Soda Springs, in the Sierra Nevada Range of California, received 17 inches of snow in less than 24 hours.

1989
Brutal northwest winds ushered bitter cold arctic air into the north central U.S. International Falls and Warroad, MN tied for the cold spot in the nation with morning lows of -34°. Minot, ND reported a wind chill reading of -81°. Locations reporting record low temperatures for the date included: Green Bay, WI: -15°: Tied, Springfield, IL: -14°, Peoria, IL: -12°, Paducah, KY: 4°-Tied, Wallops Island, VA: 7°, Sterling (Dulles Airport), VA: 9°, San Angelo, TX: 17° and Redding, CA: 29°.
Squalls produced more heavy snow in the Great Lakes Region. Erie, PA received 21 inches of snow, including 4 inches in one hour, to bring their total snow cover to 39 inches, an all-time record for that location.

1990
Areas from the Plains to the West Coast were under the influence of a dangerously cold arctic air mass. Strong northern winds produced wind chill temperatures of -45° to -55°. Locations reporting record low temperatures for the date included: Wisdom, MT: -39°, Casper, WY: -36°, Chinook, MT: -31°, Boulder, MT: -30°, White Sulphur Springs, MT: -30°, Cut Bank, MT: -29°, Fort Assiniboine, MT: -29°, Lewistown, MT: -28°, Great Falls, MT: -28°, Stanford, MT: -27°, Conrad, MT: -26°, Helena, MT: -25°, Sheridan, WY: -25°, Virginia City, MT: -25°, Livingston, MT: -24°, Billings, MT: -22°, Valentine, MT: -21°, Ely, NV: -20°, Winnemucca, NV: -19°, Denver, CO: -16°: Tied, Pocatello, ID: -13°, Pendleton, OR: -12°, Boise, ID: -8°, Salt Lake City, UT: -7°, Olympia, WA: 4°, Medford, OR: 8°, Astoria, OR: 9° (broke record by 13 degrees), Salem, OR: 9°, Seattle, WA: 14°, Quillayute, WA: 18°, Redding, CA: 22° and Sacramento, CA: 23°.

Snow fell at Santa Maria, CA for the first time since records were kept.

1996
Many locations reported record low temperatures for the date including: Greensboro, NC: 13°-Tied, Greenville-Spartanburg, SC: 13°-Tied, Shreveport, LA: 16°, Baton Rouge, LA: 18°, Lake Charles, LA: 21°, Houston, TX: 21°, Del Rio, TX: 23°-Tied and New Orleans, LA: 25°.

During the day, record cold afternoon highs occurred across the state of Florida. No reporting stations made it to 60, an unusual occurrence. Locations reporting record low maximums for the date included: Gainesville: 40°, Jacksonville: 40°, Tampa: 44°, Daytona Beach: 45°, Orlando: 46°, West Palm Beach: 55° and Key West: 58°.

1997
Waco, Texas recorded 7.98 inches of rain in 24 hours, the city's all-time 24 hour rainfall record.

1998
Snow showers fall on the central San Joaquin Valley during the late evening, whitening lawns in the Fresno-Clovis metropolitan area. This is the last time on record that measurable snow has fallen in Fresno with a half inch measured at Fresno Yosemite International Airport by the Air National Guard.

Locations from the Rockies to the West Coast reporting record low temperatures for the date included: Butte, MT: -36°, Del Bonita, MT: -29°, Missoula, MT: -20°, Quillayute, WA: 18°-Tied, Eureka, CA: 27° and Santa Maria, CA: 27°-Tied.

2005
Heavy snowfall in December reached near record levels in parts of Japan. In the western prefecture of Fukui, more than 78 inches accumulated. Snow-related power outages hit 650,000 homes and businesses in the northern prefecture of Niigata. On the 25th, an express train derails in northern Japan due to the snow. Six fatalities are blamed on the severe winter weather.

2006
A powerful low pressure system over southeast Colorado produced a major blizzard across much of the region. Snowfall totals generally ranged from one to two and a half feet. Heavy snow combined with winds gusting from 40 to 55 mph produced whiteout conditions and drifts from 5 to 12 feet. Denver International Airport was closed for 45 consecutive hours.

This was the longest closure in the hubs 12 year history. Nearly 2,000 flights were canceled and 5,000 travelers stranded. Cheyenne, WY recorded their all-time greatest daily snowfall for December with 12.5 inches while a report of 23 inches was received from near Chugwater. Colorado snowfall totals included: Conifer: 42 inches, Evergreen: 40 inches, Aspen Springs: 39 inches, 10 miles southeast of Buckley Air Force Base: 34 inches, Nederland: 33 inches, Littleton: 32 inches, Intercanyon: 31 inches, Atop Buckhorn Mountain: 30.5 inches, Thornton & Castle Rock: 30 inches, Parker: 29.5 inches, Rollinsville: 29 inches, Wheat Ridge: 28 inches, Centennial Airport: 25.5 inches, Niwot: 25 inches, Aurora: 24 inches, Greenwood Village: 22.5 inches, Atop Crow Hill: 22.4 inches, Arvada: 22 inches, Lakewood: 21.5 inches, Denver International Airport: 20.7 inches, Longmont & Georgetown: 20 inches, and 15.7 inches at Boulder. Essentially all roads were closed over the area and more than 20 tractor-trailer trucks were stranded along Interstate 80 in the Nebraska panhandle.

Sadly, one life was lost due to the storm. In Denver, snow cover of an inch or more from this and subsequent storms persisted for 61 consecutive days through 2/19/2007, the second longest period of snow cover on record for the city.

Severe Cyclone Bondo, the equivalent of a Category 5 hurricane, approached the northern Madagascar coast with sustained winds of 160 mph.