May 2012 Climate Summary

May 2012

Central Indiana 

Climate Summary

Tied for 5th Warmest on record at Indianapolis
Warmest May since 1977 at Indianapolis

42nd Driest on record at Indianapolis
Driest May since 2007 at Indianapolis



Temperatures started the month out warm as a frontal boundary oscillated across the Ohio Valley through May 7.  Much of central Indiana was along and south of the boundary with high temperatures commonly in the upper 70s to middle 80s. The frontal boundary finally moved away from the region on the 8th, ushering in the coolest days of May.  High temperatures were in the upper 60s and lower 70s and lows falling back into the 40s.  A few locations even bottomed out in the upper 30s on the mornings of the 9th and 10th.

High pressure remained the dominant influence over central Indiana and much of the Ohio Valley through the middle of the month, bringing dry weather with plenty of sunny days and mainly clear and cool nights. Temperatures were near average with highs in the 70s to around 80 and lows ranging from the middle 40s to middle 50s from the 11th through the 17th.  Beginning on the 18th, an upper ridge expanded into the Ohio Valley with high temperatures warming into the upper 80s and lower 90s on the 19th and 20th.  The passage of a weakening cold front on the 21st brought temperatures back down into the upper 60s and lower 70s for much of central Indiana. The cool down was temporary.  A steady warming trend commenced on the 23rd and persisted right through the Memorial Day weekend.  Indiana experienced the warmest weather of the year to date as highs on the 26th, 27th and 28th topped out in the lower and middle 90s. This was the longest and hottest heat wave since early September 2011.   A passing cold front brought relief to the state on the 29th.  May ended on the mild side.



May 2012     Avg Temp

May 2012 Difference from Normal



Lowest Temperature




92 on 28

42 on 10




93 on 26, 27 and 28

38 on 10 and 11




94 on 27

41 on 10 and 11

Terre Haute



96 on 27, 28

42 on 10




92 on 27, 28

41 on 10




93 on 26, 27 and 28

44 on 10

Indy – Eagle Crk.



91 on 27, 28

45 on 10 and 11


At Indianapolis, there were 23 days with above normal average temperatures, 4 days with below normal average temperatures and 4 days with a normal average temperature.


May 2012 tied for the 5th warmest in the Indianapolis area since 1871.




May was another dry month in much of Indiana especially in portions of southwest and northeast Indiana.  Monthly rainfall totaled from around one-half of an inch in southwest and northeast Indiana to more than 9 inches in Harrison County in extreme south central Indiana.  Most areas received between 1 and 4 inches of rainfall during May.

Rainfall was not evenly distributed during May.  Most locations went from 20 to 26 days with very little rainfall.  Rainfall was nearly absent from the state from the 10th through 28th. 

Drought conditions expanded during the month of May.  The U.S. Drought Monitor on May 29th indicated 50% of the state in drought conditions.  Dry conditions in Vigo and Sullivan counties prompted county wide burning bans during the latter part of May.  Replanting of crops was necessary in some areas because of drought stress.

Rainfall on May 29th in central and southern Indiana and cooler weather alleviated dry conditions to some extent.  Significant rainfall during the waning hours of May and continuing into early June provided some additional relief.

Rainfall of 1 to 3 inches in central Indiana on May 1st caused localized high water and bankfull conditions along the Eel, White and East Fork White Rivers during the first week of May.  Rainfall of 3 to 6 inches in portions of Jackson, Washington and eastern Lawrence counties on the evening of May 4th caused brief flooding along the Muscatatuck River in southwest Jackson County.


May 2012 Precipitation

May 2012 Difference from Normal

Wettest Day

Longest Dry Stretch




1.48 on 1

 11 days 10-20




0.87 on 1

 10 days 10-19




1.41 on 7

 11 days 10-20

Terre Haute



0.92 on 1

 15 days 14-28




0.90 on 7

 10 days 10-19




0.94 on 1

 11 days 10-20

Indy – Eagle Crk.



1.11 on 1

 11 days 10-20


May 2012 was the 42nd driest in the Indianapolis area since weather records began in 1871.



Severe Weather


A nearly stationary frontal boundary across the region produced periodic showers and thunderstorms throughout the first week of the month.  The bulk of the severe weather took place on the 1st as a strong disturbance moved through central Indiana. Thunderstorms impacted areas mainly south and east of Indianapolis during the afternoon, producing damaging winds and large hail.  Wind gusts over 70 mph were recorded in Decatur and Henry Counties with thunderstorms.  A weak EF0 tornado developed near Cory in Clay County. Focus then shifted to a supercell that moved into the northern Wabash valley during the evening. This storm produced hail, numerous wall clouds, funnel clouds and a couple of tornado sightings across eastern Illinois and into western Indiana.  The storm continued to track east-southeast, producing an EF0 tornado near Yeddo in Fountain County and an EF1 near New Ross in Montgomery County. This supercell eventually weakened as it approached the Indianapolis metro area.


Additional strong to severe thunderstorms occurred on the evenings of the 4th, and 6th, and the afternoon and evening of the 7th. Flooding occurred in Ellettsville on the evening of the 7th, as Jacks Defeat Creek rose rapidly after three inches of rainfall fell across western Monroe County.  A few homes were evacuated as a precaution near where the creek crosses State Route 46.


Scattered thunderstorms developed in advance of a weakening cold front on the 20th and 21st, producing small hail, gusty winds and locally torrential rainfall.


For information on severe weather in other areas during May, visit the Storm Prediction Center “Severe Weather Event Summaries” website at




The maximum wind gust at Indianapolis International Airport was 36 mph out of the northwest on the 7th with thunderstorms in the area.  Fog or haze was reported at Indianapolis on14 days during the month.  Dense fog was recorded on the 1st. Thunder was reported on 7 days during the month, with a report of hail at the airport on the 1st.


June 2012 Outlook


The official outlook for June 2012 from the Climate Prediction Center indicates a higher chance of above normal temperatures for central Indiana.  At Indianapolis, the average temperature for June is 72.0 degrees.  The outlook also calls for an equal chance of above normal, normal or below normal precipitation. The average rainfall for June at Indianapolis is 4.25 inches.



Data prepared by the Indianapolis Forecast Office.

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