Meteorological summer spans from June 1 to August 31. Locally, this has been a rather cool summer with plenty of moisture. There were only two days this summer where the temperature reached 90F (32C) or higher. Interestingly, both days were in June on the 24th and 26th of the month. The temperature reached 93F (34C) on both days. June's mean temperature was 71.3F (21.8C). The highest temperature in July was 86F (30C) on the 10th. July was a very cool month with a mean temperature of only 68.5F (20.2C). The warmest temperature in August was 88F (31.1C) on the 27th. The mean temperature in August was 70.1F (21.1C). The coolest temperature of the summer was on June 5, when the mercury dropped to 45.4F (7.4C). The temperature also dropped to 48F (8.8C) on the 6th. The temperature didn't drop into the 40's again until the last two days of August when the temperature dropped to 48F (8.8C) on the 31st.
Precipitation was plentiful during the summer of 2009. For the entire summer, 14.96 inches (380mm) of rain fell. The wettest month was July with 6.01 inches (152.7mm) falling while June was the driest with only 3.65 inches (92.7mm) falling. During August, 5.30 inches (134.6mm) of rain fell. Most of the rain fell on August 4 with very little rain falling the rest of the month causing some dry conditions.
Here's more information about the rest of Central Indiana from the NWS in Indianapolis.
Summer Climate Summary for Central Indiana
Climatological summer covers the months of June, July, and August. During that period, temperatures averaged below normal across central Indiana. The coolest month during the summer was July. July temperatures averaged 3.5 to 6.5 degrees below average, and the only first order station to reach 90 degrees during the month was Muncie. July 2009 was the 2nd coldest July on record for Indianapolis.
Warm periods did occur in June and August. Most sites saw their warmest periods of the summer in late June, when readings topped out in the lower to middle 90s. Another warm spell occurred in mid August. Interestingly, both the coldest and warmest temperatures for the season happened in June for most sites. The first week of June saw temperatures in the 40s across much of the area. The last week of August also saw readings in the 40s for many areas.
Central Indiana was split in terms of precipitation during the summer, with many areas north of Interstate 70 seeing below normal precipitation and areas south of I-70 seeing above normal precipitation. Muncie had a little over 50% of the rainfall normally seen during the summer, while Indianapolis had 130%. It was an even wetter summer just south and east of Indianapolis. Portions of Shelby, Decatur, Brown, Bartholomew, Jackson and Jennings counites received over 20 inches of rain during the summer. This is nearly twice the normal summer rainfall.