Highlights: A cold snap struck Florida on December 14-15, causing additional harm to tender vegetables and requiring producers to use wind and water techniques to help protect crops such as oranges, strawberries, and sugarcane. Warmer weather returned to Florida by week's end, allowing farmers to begin assessing the impacts of the freezes. Cold weather dominated areas along and east of a line from eastern Montana to Louisiana, with weekly temperatures averaging more than 15 degrees Fahrenheit below normal in the lower and middle Ohio Valley. Sub-zero readings were common across the northern Plains and the upper Midwest, while freezes were noted as far south as interior southern Florida. In the wake of Florida's freeze, widespread, generally light precipitation fell across the eastern one-third of the Nation. Precipitation was heaviest in New England, where 2- to 8-inch totals were reported. Snow fell in parts of the Midwestern and Mid-Atlantic States, as well as the interior Northeast. By week's end, the Midwest retained a widespread snow cover, with depths of 1 to 2 feet persisting in the upper Mississippi Valley. In contrast, mostly dry weather prevailed on the Plains.

A snow cover continued to protect the northern Plains' winter wheat crop from weather extremes, but developing drought maintained stress on wheat across parts of the central and southern Plains. A late-week storm provided generally light but beneficial snow across Texas' northern panhandle and neighboring areas. Elsewhere, Western wetness shifted southward. Pacific Northwestern weekly precipitation totals of 4 inches or more were common, while a parade of storms began to arrive in California. Although the Western storminess was overall favorable for water-supply prospects, flash flooding and mudslides occurred in parts of southern California. In advance of the storminess, Southwestern weekly temperatures averaged as much as 10 degrees Fahrenheit above normal.

Early in the week, cold air spread from the Midwest into the Southeast in the wake of a departing storm, while warmth expanded across the West in advance of Pacific storminess. On December 12, daily-record highs in California included 89 degrees Fahrenheit in San Gabriel and 88 degrees Fahrenheit in Camarillo. A day later, Indio, California (89 degrees Fahrenheit); Tucson, Arizona (84 degrees Fahrenheit); and Pueblo, Colorado (73 degrees Fahrenheit), were among dozens of locations to post daily-record highs, while International Falls, Minnesota (-33 degrees Fahrenheit), notched a daily-record low. A record-setting chill returned to Florida on December 14, when lows included 20 degrees Fahrenheit in Jacksonville, 24 degrees Fahrenheit in Vero Beach, and 32 degrees Fahrenheit in West Palm Beach.

Farther north, lows for December 14 fell to daily-record levels in locations such as Merrill, Wisconsin (-24 degrees Fahrenheit); Lincoln, Illinois (-4 degrees Fahrenheit); and Paducah, Kentucky (4 degrees Fahrenheit).

Interestingly, Caribou, Maine (57 degrees Fahrenheit), notched a daily-record high for December 14, while highs in Florida peaked at 45 degrees Fahrenheit in Jacksonville, 48 degrees Fahrenheit in Daytona Beach, and 53 degrees Fahrenheit in Miami. On December 14-15, Miami Beach, Florida (36 degrees Fahrenheit both days), collected consecutive daily-record lows. Additional Southeastern records for December 15 included 10 degrees Fahrenheit in Greenville-Spartanburg, South Carolina, and 31 degrees Fahrenheit in Sarasota-Bradenton, Florida. Meanwhile, warmth spread into the south-central United States, where records in Texas for December 15 reached 86 degrees Fahrenheit in San Angelo and 84 degrees Fahrenheit in Wichita Falls.

As the week began, heavy precipitation fell in both the Northeast and the Northwest. In the latter region, 21.0 inches of snow blanketed Mazama, Washington, in a 24-hour period on December 11-12. It was Mazama's third-snowiest 24-hour period in December, behind 28.5 inches on December 8-9, 1987, and 21.5 inches on December 28-29, 1996. Elsewhere in Washington, daily-record rainfall totals for December 12 included 3.10 inches in Shelton and 2.19 inches in Seattle. The Snoqualmie River near Carnation, Washington, crested 4.61 feet above flood stage on December 13, representing the highest water level in that location since January 2009. Meanwhile, December 12-14 rainfall exceeded 8 inches at a few locations in Washington County, Maine. Northeastern daily-record amounts for December 12 reached 2.44 inches in Islip, New York, and 2.10 inches in Bridgeport, Connecticut.

In the Midwest, daily-record snowfall totals for December 12 included 12.3 inches in Marquette, Michigan; 4.4 inches in St. Louis, Missouri; 4.1 inches in Indianapolis, Indiana; and 3.0 inches in Bowling Green, Kentucky. Snow squalls continued for days downwind of the Great Lakes, with Syracuse, New York (11.9 inches), netting a daily-record total for December 15. Syracuse received 70.9 inches of snow during the first 18 days of the month, edging its December 2000 standard of 70.3 inches. Farther west, the snow depth in Rochester, Minnesota, climbed to 26 inches on December 17.

The only greater depths in Rochester's history occurred from January 23-25, 1982, when 27 to 29 inches of snow covered the ground. By December 16, another round of generally light snow spread from the Midwestern to the Mid-Atlantic States. Daily-record amounts for December 16 totaled 4.1 inches at Cincinnati, Ohio, and 1.0 inch at Wallops Island, Virginia. At the same time, a disturbance crossing southern portions of the Rockies and High Plains produced a daily-record precipitation total (0.96 inch on December 16) in Albuquerque, New Mexico, and a daily-record snowfall (6.0 inches on December 17) in Dalhart, Texas. At week's end, storminess began to engulf the West. In California, daily-record rainfall amounts for December 17 reached 1.12 inches in Fresno and 0.85 inch in Hanford. Reno, Nevada (5.3 inches on December 17), collected a daily-record snowfall. On December 18, daily-record amounts in California reached 3.14 inches in Santa Maria and 1.37 inches in Bakersfield. For Bakersfield, it was the wettest December day in more than 120 years of record-keeping, supplanting 1.02 inches on December 27, 1936. (The record was broken again on December 19, when 1.53 inches pelted Bakersfield.) Through December 19, the average water content of the Sierra Nevada snow pack stood at 16 inches (197 percent of normal for the date), up from 8 inches less than a week earlier. Meanwhile in Kansas, Wichita's spell without measurable precipitation stretched to 31 days (November 18 - December18).

Cold, mostly dry weather continued in Alaska, where weekly temperatures averaged more than 20 degrees Fahrenheit below normal at some interior locations. During the first half of month, the average temperature of -17.3 degrees Fahrenheit in Fairbanks represented the coldest December 1-15 period in that location since 2001. On December 15-16, readings dipped below -50 degrees Fahrenheit at a few interior locations, including Fort Yukon.

Meanwhile, a high-wind event on December 15 in south-central Alaska resulted in a gust to 81 miles per hour at the Palmer Airport. Farther south, several days of warm, dry weather in Hawaii yielded to a wet pattern across the western and central islands. On Oahu, Maunawili netted 4.38 inches of rain in a 24-hour period on December 18-19. Prior to the rain's arrival, daily-record highs included 87 degrees Fahrenheit (on December 14) in Kahului, Maui, and 84 degrees Fahrenheit (on December 15) in Lihue, Kauai.