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August tied 12th hottest on record in Central Indiana
August 2021’s abnormally hot temperatures averaged about three degrees above normal across all of central Indiana, which included both a mild first week and a consistently very warm to hot pattern for the remainder of the month, the National Weather Service at Indianapolis reports.
Heat waves occurred during Aug. 10-12 and Aug. 24-29, wherein nearly all daily temperatures averaged about 10 degrees above normal for most locations. This was the hottest August for the Indianapolis area since 2016, as well as the first year with an August hotter than July since 2016.
The monthly maximum was reached on the 24th with most locations reaching the mid 90s and 97 degrees the highest mark reached at any site. Daytime highs of more than 90 degrees were common through August, tallying from eight days at Lafayette to 12 at Shelbyville. Shoals in Martin County counted 16 days at 90 or higher.
Indianapolis reached 80 degrees or higher on every day for only the fifth time in the area’s 150-year record. Normally six days in August have high temperatures less than 80.
At Indianapolis, August 2021’s daily average temperatures were above normal on 23 days and below normal on seven days. It tied for the 12th hottest August for the Indianapolis area since weather records began in 1871, placing it in the 92 percentile.
August is normally central Indiana’s driest summer month, as three to 3.5 inches of rain is normally seen by most locations, typically 1-1.5 inches less than June and Julys totals. This year certainly exemplified the climatological pattern with most of the region totaling 1.50-4 inches, including only 1.99 inches at the Indianapolis international Airport, which was only 62 percent of normal.
The highly variable monthly totals across the region were driven by several days of isolated scattered heavy rains from thunderstorms, particularly during the last two weeks of the month.
However, most locations saw below normal rainfall for the month, some spots significantly so. Greencastle logged 2.52 inches for the month. Lowest reported totals were 0.67 inches near Paragon (Morgan County), and 0.70 inches southwest of Thorntown (Boone County).
Heaviest daily rainfall reports included 2.17 inches near Noblesville from the storms of the 19th; 4.38 inches in Avon on the 25th; 2.34 inches at Kokomo on the 26th; 4.40 inches near Muncie the night of the 29-30th; and 3.92 inches near Shoals on the 30th when flooded roads were reported across Lawrence County.
Despite below-normal precipitation in August, the Indianapolis area’s year-to-date total of 31.31 inches through Aug 31, is still 0.41 above normal. July 2021 was the 39th driest for the Indianapolis area since weather records began in 1871.
Thunder was reported on nine days at Indianapolis, with the frequency at other airports ranging from six days at Terre Haute to 10 at Indy-Eagle Creek.
The official outlook for September from the Climate Prediction Center indicates an equal chance of above, below or near normal temperatures for central Indiana. The normal September temperature for Indianapolis is 67.8 degrees.
The normal September precipitation at Indianapolis is 3.14 inches.