2013 Summer Climate Summary


Central Indiana

 Summer 2013 Summary



After the very hot summer experienced in 2012, the summer of 2013 saw a return to near to slightly below normal temperatures across the Hoosier state. Many locations across central Indiana experienced average temperatures one to two degrees below normal.  After reaching or exceeding 90 degrees on 48 days during the 2012 summer, the Indianapolis International Airport made it to 90 degrees on only 11 days this summer.


After a period of wetter conditions in June and early July for many locations in central Indiana, the second half of the summer was progressively drier. This resulted in much of the region finishing the summer season 1 to 3 inches below normal. Indianapolis received only 1.15 inches of precipitation in August, good for the 12th driest August on record. The following is a summary of weather conditions experienced in Central Indiana during the months of June, July, and August 2013.
The summer of 2013 was tied for the 62nd coolest summer ever at Indianapolis, with an average temperature of 73.6 degrees. The normal summer average temperature is 73.9 degrees, making this summer below normal by 0.3 degrees.  This was the coolest summer since the summer of 2009, when the average temperature was 72.4 degrees.
June started off slightly cooler than normal but quite pleasant, as highs largely remained in the 70s. In the wake of a cold frontal passage, much of central Indiana fell into the middle and upper 40s on the morning of the 3rd, with several locations not making it out of the 60s for highs that day. For much of the region, the 3rd would be the coolest day of the month. Temperatures warmed over the next several days, with highs ranging from the middle 70s to lower 80s common across the area through the 10th.
Beginning on the 11th, warm and humid air expanded north into the Ohio Valley as a warm front lifted into the Great Lakes. Temperatures surged into the 80s, culminating with sultry highs in the upper 80s and lower 90s on the afternoon of the 12th. The passage of a cold front early on the morning of the 13th would bring a drier and slightly cooler airmass back south across the region with highs settling into the lower and middle 80s through the 20th as central Indiana enjoyed a predominantly dry stretch of weather with high pressure in place.

A warm front shifted north into the Great Lakes on the 21st as a large upper ridge developed across the central Plains. With southerly winds pumping warm, moist air into the Ohio Valley, high temperatures once again rose into the middle and upper 80s, with a few locations even making it into the lower 90s, through much of the remainder of the month with a noticeable rise in the humidity levels. Scattered thunderstorms were a daily occurrence across central Indiana through the 28th, then became more numerous as an upper level low pressure system meandered across the Ohio Valley on the 29th and 30th. High temperatures fell back into the lower and middle 70s for the last two days of the month as clouds and rainfall were in abundance across the region. The Indianapolis International Airport failed to reach 90 degrees in June for the first time since June 2006, and remained in search of its first 90-degree day of the year. By the end of June in 2012, Indianapolis had already made it to 90 degrees on 15 days.




July got off to a cool start as a persistent upper low meandered across the Ohio and mid Mississippi Valleys. High temperatures through the first six days generally remained in the 70s to lower 80s. The departure of the upper low enabled a warmer and more humid airmass to return to the region beginning on the 7th with highs rising into the middle and upper 80s. A few locations even made it into the lower 90s on the 9th. The passage of a cold front on the 10th ushered in a brief period of slightly cooler temperatures and noticeably less humid air with highs in the lower 80s and lows in the lower and middle 60s.
The hottest weather of the month arrived beginning on the 14th as a large upper level ridge expanded east into the Ohio Valley. High temperatures returned to the upper 80s to near 90 on the 14th and 15th in many locations, followed by highs rising into the lower and middle 90s from the 16th through the 19th. A cold front brought an abrupt end to the heat on the 20th with highs reverting back into the lower 80s. High temperatures returned into the upper 80s and lower 90s briefly on the 23rd as the front lifted back north into the region.
The cold front moved back south late on the 23rd, ushering in much cooler and drier air into the Ohio Valley and Great Lakes. A broad upper level trough would build into the region and keep cooler temperatures across central Indiana for the rest of the month. High temperatures generally remained below 80 degrees for the last eight days of the month, impressive for late July. At Indianapolis, every day from the 24th through the 31st experienced temperatures in the 70s. This tied a long standing record for most consecutive days with highs under 80 degrees in the capital city, a record that had stood since 1871. A reinforcing shot of cooler air brought lows on the 28th and 29th into the upper 40s and lower 50s across central Indiana. Indianapolis set a record low of 51 degrees on the morning of the 28th, breaking the old record from 1971 and 2004 by three degrees. The average temperature was generally ten degrees cooler across central Indiana for this July compared to July 2012. After reaching 90 degrees or greater on 28 days in Indianapolis in July 2012, the mercury made it to 90 degrees on only 5 days this July.
The summer season wrapped up with temperatures generally near to slightly below normal for most of central Indiana in August. Temperatures were seasonable for the first part of the month with highs mainly in the lower and middle 80s and lows in the 60s. The passage of a cold front on the 12th ushered in a fall-like preview with a much cooler airmass as a broad upper trough established over the Great Lakes. High temperatures from the 13th through the 16th fell back into the 70s across central Indiana, with some locations even struggling to make it to 70 degrees on the 14th. Lows fell into the 40s in rural locations with clear skies and light northerly flow.

Temperatures began to modify on the 17th, with highs returning into the middle and upper 80s through the 25th as the upper trough moved away to the east, allowing warmer and more progressively humid conditions to expand into the Ohio Valley. Highs exceeding the 90 degree mark returned for the first time in nearly five weeks beginning on the 26th as the upper ridge across the central U.S. expanded east into the region. Despite a weak boundary dropping through central Indiana on the 28th, the ridge would remain the dominant feature to end the month with many locations experiencing highs in the lower to middle 90s every day from the 26th through the 31st. Many locations along and south of Interstate 70 experienced their hottest temperatures of the year on the 31st. This included Indianapolis, which recorded a high of 96 degrees on the last day of August, 1 degree shy of the daily record. The six days of 90+ degree temperatures to end the month enabled Indianapolis to finish slightly above normal for August.


Temperature Data for Other Sites in Central Indiana

Summer 2013 Temperature
Normal Temperature
Diff. From Normal
Indianapolis Int’l Arpt
Terre Haute
Shelbyville (*)
Indianapolis – Eagle Creek

(*) – Shelbyville missing low temperature from 6/4/13 and all temperature data from 8/11/13.
Summer Extremes Across Central Indiana

Warmest Temperature
Coldest Temperature
Indianapolis Int’l Airport
96 on 8/31
48 on 6/3
93 on 7/19 and 8/30
45 on 6/3
92 on 7/18, 7/19 and 8/27
45 on 8/14 and 8/15
Terre Haute
96 on 8/31
47 on 8/15
95 on 8/31
45 on 8/15
97 on 8/31
48 on 8/31
Indianapolis-Eagle Creek
93 on 8/31
46 on 6/3






Overall this was the 33rd driest summer on record at Indianapolis. The total rainfall for Indianapolis this summer was 8.10 inches. The normal rainfall total for summer is 11.93 inches, which made this summer below normal by 3.83 inches.



June was on the dry side for much of Indiana for the first three weeks of the month, but turned wetter during the last third of the month. Daily showers and thunderstorms occurred across various portions of the state beginning on the afternoon of the 21st and continuing through the end of the month. At times, torrential downpours produced localized flooding or flash flooding in portions of central and southern Indiana on the 21st, 22nd, 23rd, 24th, and 26th. Additional thunderstorms brought soaking rains and localized flash flooding to parts of central Indiana on the 29th and 30th as an upper level low pressure system developed over the Ohio Valley.

The largest rain event during June occurred in southwest and south central Indiana. In a 24 hour period from the evening of the 25th through the evening of 26th, torrential rains of 3 to nearly 8 inches fell. Flash flooding quickly transitioned into low land river flooding along portions of the Lower White and Wabash Rivers. Overall monthly rainfall totals for June ranged from around 3 inches in Johnson County in central Indiana to more than 10 inches in portions of Greene, Clay, Sullivan, Vigo, Knox and Martin Counties of west central and southwest Indiana. This was the third consecutive month where portions of Indiana received at least 10 inches of rain.

River flooding was frequent during June. River flooding began at the very beginning of June along portions of the Wabash, Tippecanoe and White Rivers following rainfall of 3 to more than 6 inches during end of May and beginning of June in western and northern Indiana. This river flooding ended by the 11th. River flooding returned again on the 13th to portions of the Tippecanoe and Wabash River. Rainfall of 2 to nearly 6 inches occurred in north central and east central Indiana from the 9th through the 13th. The White River in central Indiana approached bank full levels following this rain. River flooding along the Wabash ended by the 22nd. The last river flood event of June began swiftly along the lower reaches of the White and Wabash Rivers following the flash flooding during the evening of the 26th. This was the third time during June that the Wabash River in the Hutsonville, Illinois and Riverton Indiana area flooded. The flood along the White River in southwest Indiana was the highest since April. River flooding continued into early July along portions of the lowest reaches of the White and Wabash Rivers in southwest Indiana.



July was a rather dry month for much of Indiana. Monthly rainfall totals ranged from near 1 inch in portions of central and northern Indiana to over 10 inches in a very small portion of southwest Indiana. Much of the state received 2 to 4 inches during July. Favored areas for rainfall during July included much of west central Indiana, southern Indiana near the Ohio River and far northeast Indiana. Many locations in these areas received 4 to more than 6 inches of rain. The driest area of the state was portions of northwest Indiana where less than an inch of rain fell.

Heavy rainfall on the 1st and 2nd in southwest Indiana and southeast Illinois prolonged high river levels and caused lowland flooding along the lower Wabash River from immediately north of Vincennes to the Ohio River. Confined areas of heavy rainfall of 3 to 5 inches occurred on the 10th, 20th and 23rd and caused localized flooding, but no river flooding. After the 2nd, rainfall of less than an inch fell in many areas during the remainder of the month.

According the US Drought Monitor of July 23, abnormally dry condition existed in portions of east central Indiana. Below normal precipitation has fallen in much of this area since October 1, 2012. The US Geological Survey Water Watch indicated below normal stream flow for the 14 day period ending July 31 in much of the area.



August was a dry month for much of Indiana. Monthly rainfall totals ranged from around a tenth of an inch in south central Indiana to over 6 inches in northwest Indiana. Much of the state received one-half to 3 inches during August. Rainfall during August was sporadic in central and southern Indiana. Only two relatively heavy rainfall events occurred. On the 8th, southeast Marion and northwest Shelby counties received 1.5 to nearly 3 inches of rainfall that caused localized flooding. On the 20th, a small portion of southwest Jackson County received 1 to 2 inches of rain.

The only elevated river levels during August occurred along the Wabash River from the 4th to the 9th in the Lafayette and Covington areas as a result of significant upstream rains. Much of northern Indiana received one-half to more than 4 inches of rain on the 2nd. The heaviest rainfall was concentrated in the Columbia City and Huntington areas located in the upper northeast portion of the Wabash watershed.
A prolonged dry spell began in much of central Indiana around the 10th and continued for much of the remainder of the month. Little or no rain fell in all Indiana for the 7 day period ending 8 am EDT on the 20th. The Indianapolis airport received no measurable rainfall from the 10th through the 30th. Trace amounts did fall on the 10th, 16th and 28th. This was the first extended dry period of the summer and the longest since June-July 2012. More widespread thunderstorms impacted northern portions of central Indiana on the evening of the 30th as a weak upper level disturbance passed through the region. Many locations, especially along and south of Interstate 70, received generous rainfall on the afternoon and evening of the 31st as strong to severe thunderstorms impacted the region. One to two inches fell in several locations over southern portions of central Indiana.


The U.S. Drought Monitor indicated that abnormally dry conditions existed in much of central Indiana as of August 27th. The U.S. Geological Survey Water Watch indicated below normal stream flow for the 7 day period ending August 28 in much of central and southern Indiana. This included the entire Wildcat Creek watershed, all of the White River downstream of Indianapolis and the entire East Fork White River. Local reservoirs were approaching a foot below normal levels.


Rainfall Data for Other Sites in Central Indiana

Summer 2013 Rainfall
Normal Rainfall
Diff. From Normal
Indianapolis Int’l Arpt.
Muncie (*)
Terre Haute
Bloomington (**)
Indianapolis – Eagle Creek

(*) – Muncie missing precipitation for 7/30/13.

(**) – Bloomington missing precipitation for 6/28-6/30/13.



Major Weather Events
The summer season got off to a stormy start right away as a weakening squall line moved across the western part of central Indiana during the early morning of the June 1st, producing sporadic wind damage. A large thunderstorm complex impacted much of the northern part of central Indiana during the late evening and early morning of the June 12th and 13th ahead of a strong cold front. The storms predominantly produced damaging winds and torrential rainfall. There were a few reports of large hail as well. Isolated severe thunderstorms affected southern portions of central Indiana during the early evening of the 18th.
During the morning and afternoon of June 21st, a large thunderstorm complex moved from the upper Mississippi Valley southeast into the southern Wisconsin and northern Illinois, producing severe weather and flooding. The complex gradually weakened as it tracked into the northern Wabash Valley during the evening, producing gusty winds to the northwest of Indianapolis before it diminished. This would be the start of an active period for central Indiana, with rain and thunderstorms impacting portions of the area for the rest of the month. The region remained on the fringe of a strong ridge aloft centered over the central Plains with scattered thunderstorms developing as upper level waves tracked along the periphery of the ridge and across the Ohio Valley. The development of an upper low across the region by the end of June continued the daily threat for rain and thunderstorms. Isolated to scattered severe thunderstorms impacted central Indiana each afternoon and evening from the 22nd through the 27th. As the upper low developed across the Ohio Valley during the last few days of June, thunderstorms became more widespread. On the afternoon of the 29th, several cold air funnels developed in the vicinity of showers and thunderstorms. To read more about the severe weather and flooding during this time period, please visit http://www.crh.noaa.gov/ind/?n=june232613severe.
The persistent upper low remained across the Ohio Valley in early July, with isolated strong thunderstorms on both the 1st and 2nd. One storm produced 5 to 6 inches of rainfall across northern Jackson and southern Brown County on the evening of the 1st, with several roads washed out. An isolated storm on the evening of the 2nd knocked down several trees in Carmel. Scattered severe thunderstorms developed on the afternoon of July 10th along and ahead of a cold front moving through the area. Most of the storms remained north of Interstate 70, producing wind damage. Several tents at the Howard County Fair in Kokomo collapsed from strong winds, causing one minor injury. Scattered strong to severe thunderstorms producing mainly wind damage impacted parts of central Indiana on July 20th and again on July 23rd as a frontal boundary lingered over the region. The storms on the afternoon of the 20th produced very heavy rainfall and localized flash flooding southwest of Indianapolis, including several water rescues from vehicles across Greene County.
Little severe weather occurred across central Indiana in August, primarily being confined to the last day of the month. Thunderstorms impacted much of the northern half of central Indiana during the evening of the 2nd and early morning of the 3rd ahead of a cold front and again on the 8th across mainly areas along and south of Interstate 70 in advance of a wave of low pressure. Scattered thunderstorms impacted much of the northern portions of central Indiana on the evening of August 30th, producing locally heavy rainfall, gusty winds, small hail and dangerous lightning which impacted outdoor events. Thunderstorms once again erupted during the afternoon of August 31st as an upper level wave moved through the region, producing severe weather for the first time in five weeks across the region. The storms gradually shifted south across central Indiana through the evening, impacting much of the region along and south of the Interstate 70 corridor. Outdoor events on the holiday weekend were once again affected by the weather, as storms exhibited plenty of cloud to ground lightning strikes and locally torrential rainfall. Several thunderstorms also produced large hail and damaging winds, particularly across Putnam and Vermillion Counties, and also across the western Indianapolis metro area during the late afternoon. Thunderstorms continued to produce gusty winds which knocked trees and limbs down through the evening, particularly across Knox County and near Vincennes.

For information on severe weather in other areas from June through August, visit the Storm Prediction Center “Severe Weather Event Summaries” website at http://www.spc.noaa.gov/climo/online/.


Fall 2013 Outlook for Central Indiana
The official outlook for the 2013 fall season (September-November) from the Climate Prediction Center indicates an equal chance of near, above or below normal temperatures across central Indiana. At Indianapolis, the average temperature for the fall season is 55.2 degrees. A greater chance of above normal precipitation exists across central Indiana through the fall. At Indianapolis, the average precipitation for the fall season is 9.94” and 1.1” of snowfall.
Data prepared by the NWS Indianapolis Climate Team
Questions should be referred to w-ind.webmaster@noaa.gov




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