Second-wettest summer ends with cooler August

A summer that failed to produce a single 90-degree day during August will go down as the second wettest in central Indiana history, the National Weather Service reports.

Monday officially closed the books on meteorological summer (June 1-Aug. 31), which ended up slightly cooler than normal for many locations, but in general was warmer than the previous two summers in 2013 and 2014.

The Indianapolis International Airport recorded 90 degrees on only six days throughout the summer, but posted not one 90-degree day in August for the first time since 2004. The six 90-degree days fall far below the average summer that sees 21 such days.

The record for 90-degree days in a summer is 58, set in 1983, while 2004 is the only time in history that central Indiana recorded zero 90-degree days during the summer.

Summer 2015 will go down as one of the wettest on record for many areas, due to exceptionally wet, stormy weather experienced throughout June and July. More than 23 inches of rain fell at Indianapolis Airport during the season, making 2015 the second wettest summer on record.

More than 21 inches of that rain fell during June and July, highlighted by more than 13 inches in July alone, making 2015 not only the wettest July on record, but the wettest Hoosier month in recorded history.

Summer 2015 produced an average temperature of 73.4 degrees, a shade cooler than the normal summer average of 73.9 degrees.

After a cool first few days to June, temperatures warmed quickly into the middle and upper 80s by the seventh. Highs would persist in the middle and upper 80s through the middle of the month.

In July, most locations across central Indiana experienced a below-average month in regard to temperatures. The first third of the month had the most days with below-average temperatures. Temperatures remained below 80 across much of the area.

Readings trended warmer for the remainder of the month, with some cool days still interspersed. Temperatures topped the 90-degree mark on multiple days. Terre Haute recorded five days of 90 degrees or higher temperatures, while Indianapolis and Bloomington had four each.

August was a largely typical month for mid- to late-summer temperatures with one notable exception. Highs were primarily in the 80s. Central Indiana largely escaped the typical hot weather that often dominates August, with much of the area being spared of 90-degree temperatures.

Ten mornings saw lows at or below 60 degrees, the most since August 2004. Additionally, the 72.9-degree monthly average at Indianapolis made for the coolest August since 2004 and the second-coolest August since 2000.

Meanwhile, total rainfall for Indianapolis this summer was 23.05 inches. Only the summer of 1875 experienced more rainfall, when 28.99 inches fell.

The normal summer rainfall total is 11.93 inches, which means this summer in Indianapolis was above normal by a whopping 11.12 inches. Most of the rain came in June and July, with much drier conditions settling in for August.

About half of the state received more than twice the average rainfall for June. Precipitation during the month was normal to above normal for every location in the state.

For the Indianapolis area the monthly total of 8.36 inches was the seventh-wettest June on record.

After beneficial rains at the end of May, much of Indiana was dry the first week of June. Beginning on the afternoon of June 7 and continuing the remainder of the month, various storm systems brought at times torrential rains to parts of the state.

A series of storms June 12-18 dropped 4-8 inches of rainfall. Quickly following, the remnants of tropical storm Bill brought 3-8 inches of rain on the 19th and early on the 20th to previously dry southern Indiana.

The last widespread rains of the month were the result of a low-pressure area that moved through the state June 26-27. Much of the state along and north of I-70 received 2-5 inches of rain.

That rainfall resulted in significant river flooding to the Tippecanoe, and the Wabash rivers. River flooding began in western Indiana on June 8 and continued into July, resulting in the worst river flooding for late June and early July in 17 years or longer for many areas.

In July, for the second consecutive month, monthly rainfall totals reached historic levels in portions of Indiana. Monthly totals ranged from around an inch in parts of Vermillion County in west-central Indiana to almost 18 inches in portions of Hendricks County. Monthly totals ranged from 10 to more than 15 inches in a 20- to 40-mile wide band that extended from Lebanon in Boone County of central Indiana to Charlestown in Clark County of southern Indiana.

For Indianapolis, the monthly total of 13.14 inches set an all-time monthly rainfall record besting the previous July 1875 record of 13.12 inches. During a particularly stormy period from the 7th through the 17th, the 11.54 inches of rainfall dumped on Indianapolis was the most ever for any 11-day period.

The climatological summer of 2015 was already the second-wettest of record by July 27.

Heavy rains of 3-5 inches fell mostly during the evenings of the 7th, 8th, 12th, 13th, 17th, 21st and 26th, generally in central and southern Indiana.

Some areas were flooded more than once during the month. July rainfall pushed flood levels on the White River southwest of Indianapolis to levels not seen for the middle of summer since the July and early August floods of 1979. Flooding on the White River in southwest Indiana and the lower portion of the Wabash River lasted more than five weeks while the Wabash River from Lafayette to Hutsonville in western Indiana remained above flood stage for eight weeks.

The wet summer of 2015 turned dry in many areas during August with less than an inch record in west-central and central Indiana.

The drier weather pattern continued through Aug. 13 in much of the state. Rainfall the first two weeks of August varied from 0.10 inches in west-central and central Indiana to more than 3.5 inches in east-central Indiana.

The driest portion of August was the last 12 days. Rain fell only in portions of northern and east central Indiana on the 23rd and in scattered locations statewide from Aug. 29-31.

The official outlook from the Climate Prediction Center for fall 2015 (September-November) indicates a greater chance of near-normal to slightly below normal temperatures and precipitation across central Indiana.

At Indianapolis, the average temperature for the fall season is 55.2 degrees, while the average precipitation for the fall season is 9.94 inches of rain.