The Indianapolis area marked another rare occurrence for Spring 2012...the average temperature for April was 2.1 degrees cooler than March. Typically the average monthly temperature increases nearly 11 degrees from March to April. This was only the second time since 1872 when March was warmer than April. The only other occurrence was in 1907.
It is interesting to note that both events were caused by either a record warm or record cold month. In 1907 March was followed by the coldest April of record. This year a record warm March is followed by an April with an average monthly temperature that was only 1.5 degrees above normal.
The record warmth of March resulted from an upper level ridge that remained over the Indianapolis area from March 14-22. In April an upper level trough dominated the Indianapolis weather for much of the second half of the month.
Weather records at Indianapolis began in 1871. Unfortunately all of the temperature data is missing for April 1871.