September 2010 Central Indiana Climate Summary

Tied for 21st Warmest on record at Indianapolis

4th driest on record at Indianapolis


September 2010 was a quiet weather month, perhaps too quiet when it came to precipitation.  A persistent weather pattern kept moisture away from the area and allowed above average temperatures for much of the month.  The pattern led to Indianapolis experiencing the warmest temperature so late in the year since 1953.



Monthly temperatures during September 2010 averaged from just above normal to over four degrees above normal.  While most of the month saw above normal temperatures, the week of September 19th was particularly warm.  At Indianapolis, temperatures were 10 or more degrees above normal from the 19th to the 24th.  Record high temperatures of 96 degrees on the 21st and 94 degrees on the 23rd at Indianapolis were the warmest temperature so late in the year since a 97 degree reading on September 29, 1953.  Overall, many locations across central Indiana saw between two and seven days with temperatures of 90 degrees or above.


Toward the end of the month, the weather pattern shifted so that temperatures returned to seasonal, or even below average, values.  The coolest air since May arrived, with many locations seeing highs only in the 60s from the 26th through the 28th.  Low temperatures dipped into the lower 40s during the same time frame.




September 2010 Avg Temp

September 2010 Difference from normal



Lowest Temperature




96 on 21

48 on 27, 29




94 on 21

41 on 29




92 on 21, 23

42 on 9, 27

Terre Haute



94 on 21,23

41 on 29




94 on 21,23

40 on 29




95 on 23

40 on 29

Indy – Eagle Crk.



93 on 21

45 on 29


At Indianapolis, there were eight days with below normal temperatures and 22 days with above normal temperatures.


September 2010 was tied for the 21st warmest in the Indianapolis area since 1871.





September 2010 was another very dry month for much of Indiana.  Monthly totals ranged from a September record low of around 0.10 inches in extreme south central Indiana to slightly over 4.50 inches in northern Indiana.  This was less than 5 percent of normal in portions of south central Indiana to 150 percent of normal in portions of northern Indiana.  Much of the state south of a line from Sullivan to Bluffton received less than an inch of rain for the month. 


The desert-like conditions in late August intensified during September.  The National Drought Monitor for the week ending September 28th indicated D0, or abnormally dry, conditions existed in 80 percent of Indiana with D1 and D2, or moderate to severe drought, conditions in nearly half of Indiana. 


Measurable rain fell only on four days at Muncie, Shelbyville, and Bloomington, five days at Indianapolis (International Airport), seven days at Terre Haute, and eight days at Lafayette.  The greatest amount of precipitation recorded in one day at the Indianapolis International Airport during September was 0.18 inches.


Because of the continued low rainfall since late June in many areas of Indiana, numerous small watersheds in the state were at or near record low daily flow by the end of the month.  Consequently the White, East Fork White, and Wabash Rivers were below normal with the East Fork White the lowest of these three rivers.


Much more information on the lack of rainfall and its effects can be found in this article.



September 2010 Precipitation

September 2010 Difference from Normal

Wettest Calendar Day

Longest Dry Stretch




0.18” on 11

4 days  27-30




0.59” on 1

4 days  27-30




0.44” on 22

7 days  4-10

Terre Haute



0.50” on 11

6 days  16-21




0.74” on 11

6 days  4-9




0.17” on 16 and 22

10 days 1-10

Indy – Eagle Crk.



0.23” on 19

4 days  27-30


September 2010 is the 4th driest in the Indianapolis area since 1871.


Severe Weather

No severe weather was reported during the month of September.  However, the drought conditions did lead to numerous field fires across central and southern Indiana.  Field fires occurred on the 1st, 13th, 15th, 16th, 21st, 23rd, and 30th.  One fire in Rush County charred nearly 1,000 acres and threatened a small town.  According to Indiana Forestry, some of these field fires approached extreme fire behavior.  The fires during September coincided with the highest temperatures of the month, low relative humidity values, and moderate to strong winds.


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



At the Indianapolis International Airport, the peak wind gust this month was 45 mph from the west on September 16th.  Thunder was reported on two days while fog or haze was observed on seven days.


October 2010 Outlook

The official outlook for October 2010, from the Climate Prediction Center, indicates above normal temperatures and below normal precipitation in southwest Indiana and equal chances of below, normal, or above normal precipitation for the remainder of the state.


Data prepared by Indianapolis Forecast Office.

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