December 2015 third warmest on record

While snow has been scarce so far this winter, it was late arriving in 2015, too, with most of the snowfall coming in a five-week period at the end of February and the start of March.

Closing the weather book on December and the year 2015, the National Weather Service finds December 2015 was the third warmest in the central Indiana area since weather records began in 1871.

For December, 25 days featured above-normal average temperatures, five days had below-normal average temperatures with one day at normal average temperatures.

The month started on a seasonable note with highs in the 30s through the first week. Temperatures rose after that as an upper-level ridge brought unseasonably warm weather through about the middle of the month. Highs were consistently in the 50s or warmer, peaking from Dec. 11-14 as most all of central Indiana climbed into the 60s.

Indianapolis shattered a record high on Dec. 12 when the temperature made it to 70 degrees, seven degrees warmer than the previous record set in 1877 and 1927. It was also the latest 70-degree reading in Indianapolis in recorded history.

Most of central Indiana made it into the lower 70s on the 12th, an amazing 30 degrees above normal. Overnight lows in the middle and in some areas, upper 50s, made it feel more like spring.

Indianapolis tied a record high of 64 on Dec. 23, matching the old daily record from 1933.

The area enjoyed the warmest Christmas Eve since 1982 and the warmest Christmas Day since 1987 with highs in the 50s. An unusual setup occurred along a slowly southward moving front on the early morning of the 27th as warmer air to the south of the boundary drew much warmer air into the southern half of Indiana. Many areas south of Interstate 70 rose into the 60s during overnight hours with Bloomington making it to 70 degrees around 5 a.m.

In Indianapolis, 17 days during the month experienced highs at or above 50 degrees. Only December 1877 and 1889 experienced more 50+ degree days with 18 and 22, respectively. The temperature made it to 65 or warmer on three days during the month, the most since December 2001.

The 70-degree high on Dec. 12 was the first 70-degree December day since Dec. 5, 2001.

Meanwhile, December 2015 was one of the wettest Decembers of record for Indiana.

December monthly rainfall and melted precipitation measured from slightly more than three inches in northeast Indiana to more than eight inches in west-central Indiana. Rainfall ranged from near normal in portions of southern Indiana to record amounts for December in west-central Indiana. Rainfall during the last 11 days of the month ended the dry period that persisted in much of the state since August.

Most of the December rainfall fell in the eight-day period Dec. 21-28. For the Indianapolis area, it was the wettest December since the record wet December of 1990.

The Indianapolis monthly total of 5.59 inches was a few hundredths of an inch greater than the Decembers 2006, 2007 and 2008. Much of the heavy rains of three to more than eight inches from Dec. 26-28 ran into the streams and rivers and caused extensive flooding.

December 2015 was the ninth wettest in the Indianapolis area since weather records began in 1871.

With such a warm month across the Hoosier state, little snowfall occurred during December. Snowfall was once again confined to northern and central portions of Indiana. Monthly snowfall totals ranged from less than an inch in central Indiana to two inches in northern Indiana.

With only 0.6 inches of snow in the Indianapolis area, December 2015 tied for the 30th-least snowiest December on record.

Average precipitation for January at Indianapolis is 2.66 inches, with 8.6 inches of snowfall typical.

Overall, 2015 was a year of wild swings, especially in precipitation. The year started slowly with snowfall, despite a colder-than-normal January. The most extreme weather of the winter came during February into early March as more than half of the annual snowfall fell during a five-week period. The coldest temperatures of the year occurred during the time period as well, making February the fifth coldest on record at Indianapolis.

Spring was mild with extended periods of dry weather, especially from the middle of April through most of May. The pattern shifted rather suddenly however as the month changed from May to June, transitioning to a much wetter and more unsettled weather pattern lasting through the first half of the summer.

Nearly half of the annual rainfall across central Indiana fell during June and July as frontal boundaries became nearly stationary across the Ohio Valley, setting the stage for repeated bouts of severe weather and heavy rainfall that produced flash flooding. Much of the area received in excess of 10 inches of rain during July.

For Indianapolis, not only was the 13.14 inches measured during July a record wettest July, it was also the most precipitation in any month in recorded history.

The weather pattern shifted back to a warmer and much drier regime in August, lasting through much of the fall. The longest stretch of hot weather came during the first several days of September, with many locations rising above 90 degrees for seven to eight consecutive days. For Indianapolis, it was the hottest start to a September since 1925.

Colder air and the arrival of the region's first snow held off until the middle of November for most, with no extended period of cold weather. This resulted in the fall season being the ninth warmest on record at Indianapolis.

The warm weather continued into December with weather more typical of the spring or fall at times as opposed to winter. Average temperatures were generally 11 to nearly 14 degrees above normal for the month. A rare winter severe weather event impacted central Indiana the afternoon of Dec. 23, producing wind damage and three weak tornadoes.

The year wrapped up with a widespread heavy rainfall and extensive river flooding as three to six inches of rain fell over a 48-hour period across much of the area.

Miscellaneous 2015 central Indiana weather facts:

-- Date of final spring frost: April 27.

-- Date of final measurable spring snow: March 1 (5.9 inches).

-- Date of first fall frost: Oct. 17.

-- Date of first measurable fall snow: Nov. 21 (1.3 inches).

-- Hottest high temperature: 94 (Sept. 4).

-- Coldest low temperature: -7 (Jan. 8).

-- Coldest high temperature: 9 (Feb. 19).

-- Warmest low temperature: 74 (July 19 and July 28).

-- Heaviest daily rainfall: 4.43 inches (July 7).

-- Heaviest daily snowfall: 5.9 inches (March 1).

-- Wettest seven-day period: 7.85 inches (July 7-13).

-- Most consecutive days with highs of 90 or hotter: 7 (Sept. 2-8).

-- Most consecutive days with measurable precipitation: 8 (July 7-14).

-- Most consecutive days with no measurable precipitation: 20 (Oct. 4-23).