July 2010 Climate Summary

Central Indiana
July 2010 Climate Summary
15th Warmest on record at Indianapolis
50th Driest on record at Indianapolis

The month started off on a cooler note, with below average temperatures experienced at most locations on the first few days of the month. Those dates saw low temperatures in the 50s, something that would not be seen again at most areas for the remainder of the month. Just a few days later, hot and humid conditions moved into Central Indiana and these conditions would prevail for most of the rest of the month. Even on days with scattered showers and thunderstorms, temperatures had time to reach above average.

Most areas saw temperatures at or above 90 degrees on about a third of the days during the month. At Indianapolis, 11 days of 90 or above were recorded. A typical July in Indianapolis has 7 days of 90 degrees or higher. For June and July, Indianapolis has had 16 days of 90 or higher, compared to an average of 11 days in a typical year. The highest temperature recorded during the month at many locations was around 93 degrees. At Indianapolis, the high temperature for the month of 93 degrees was the warmest temperature seen in a July since 2006.

The hot and humid airmass kept temperatures well above average during the night. Across much of Central Indiana, over a third of the month had low temperatures at or above 70 degrees. At Indianapolis, the average low temperature during July 2010 ranked the 11th warmest. Indianapolis tied the record of 78 degrees for the warmest minimum temperature on July 23. The original record for the date was set in 1933.
This was the 15th warmest July on record in terms of average temperatures at Indianapolis, and the warmest July on record since July 1999 when the average temperature topped out at 79.2 degrees.
July 2010 Avg Temp
July 2010 Difference from normal
Lowest Temperature
93 on 7,15,23,24
59 on 1
93 on 23 and 24
53 on 1
Muncie (*)
93 on 7
52 on 2
Terre Haute
94 on 7
50 on 2
93 on 7
51 on 2
92 on 7,8,15,23
51 on 2
Indy – Eagle Crk.
92 on 7,8,15,23,24
57 on 1, 2, and 3
 (*) – High Temperature Data for Muncie (KMIE) is missing for July 22.


At Indianapolis, there were 5 days with below normal average temperatures, 1 day with normal, and 25 days with above normal average temperatures.

July 2010 was the 15th warmest in the Indianapolis area since 1871.

Monthly rainfall during July in central and southern Indiana varied from slightly over 1 inch to more than 10 inches.   This was 25% to more than 200% of normal.   The wet pattern of June continued in July for much of the western portion of Indiana.  This was not true for portions of eastern Indiana.   After receiving nearly 14 inches of rain during June, one location in Rush County measured only 1 ½ inches during July.

The dry period at the end of June continued through the morning of the 8th.   Once again, a prolonged unsettled weather pattern returned to central Indiana and continued through the end of July.   The longest dry spell across the entire central and southern Indiana area was less than 3 days.  Nearly daily afternoon and evening thunderstorms occurred.  As is typical of convective rainfall, amounts varied greatly over short distances and coverage was not often widespread.  Rainfall from these storms was quite intense at times.  Several locations received 2 to more than 4 inches in a 3 to 6 hour period. 

Localized flooding did occur during July in several areas of Indiana.  The coverage and duration of the heavy rain was much less than in June.  As a result, localized flooding lasted less than 12 to 24 hours.  The heaviest rain in central and southern Indiana occurred during the evening of 17th when 3 to nearly 6 inches fell in portions of Owen and Greene Counties.  The White River in Greene...Knox and Daviess Counties reached bankfull levels as a result.

The tropical conditions of July provided Indiana field crops excellent growing conditions.  The frequent and at times abundant rainfall aided crop growth especially in much of western Indiana.  Crops in dry areas like portions of Rush County suffered during the afternoon sun.  The dry spell in early July allowed farmers to replant many areas flooded during June.   

July 2010 Precipitation
July 2010 Difference from Normal
Wettest Day
Longest Dry Stretch
0.80” on 28
7 days 1-7
0.68” on 28
7 days 1-7
0.99” on 24
7 days 1-7
Terre Haute
2.50” on 15
7 days 1-7
0.86” on 8
7 days 1-7
1.29” on 22
7 days 1-7
Indy – Eagle Crk.
1.32” on 20
7 days 1-7
July 2010 was the 50th driest in the Indianapolis area since 1871.
Severe Weather
Severe weather impacted Central Indiana less frequently in July than June. Many reports of heavy rain and localized flooding were received, including flooding near New Castle on the 13th.
Thunderstorms produced scattered wind damage on July 16, with trees knocked down the most common report. On July 17, severe storms produced 70 mph winds in the Lafayette area, downing numerous trees and causing damage to some homes. Heavy rain also fell that day, with over 6 inches of rain reported at Shakamak State Park.
A tornado touched down near Trafalgar in Johnson County on July 20. The tornado was rated EF0, and it produced damage including several trees snapped in half or uprooted, damage to a shed where the tin roof was littered into an open field, and tin siding embedded into the ground. Just a couple of days later, on July 22nd, another EF0 tornado touched down in Johnson County, this time near Greenwood. This tornado downed tree limbs, damaged roofing of some sheds, and flattened small areas of crops. 

For more detailed information regarding the above tornadoes, please visit  http://www.crh.noaa.gov/ind/?n=jul202010tor and http://www.crh.noaa.gov/ind/?n=july222010landspout

For information on severe weather in other areas during July, visit the Storm Prediction Center “Severe Weather Event Summaries” website at http://www.spc.noaa.gov/climo/online/
At the Indianapolis International Airport, the peak wind gust this month was 33 mph from the southwest on July 20. Fog or haze was observed on 17 days. Thunderstorms were observed on 12 days during the month.
August 2010 Outlook
The official outlook for August 2010 from the Climate Prediction Center indicates a greater chance of above normal temperatures for central Indiana. At Indianapolis, the average temperature for the month is 73.5 degrees. The outlook also calls for an equal chance of above or below normal precipitation. The average precipitation for August at Indianapolis is 3.82”.
Data prepared by the Indianapolis Forecast Office

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