Bloomington/Normal, IL

What the Data Says About BMI

Bloomington/Normal, IL in Bloomington/Normal, Illinois handled 25,097 flights in the Bureau of Transportation Statistics dataset between 2020 and 2025, posting a 85.2% on-time departure rate. Of those flights, 3,721 experienced delays, 297 were cancelled, and 27 were diverted. The cancellation rate works out to 1.18%, the diversion rate to 0.11%, and the average delay when departures run late is 88.2 minutes. These figures are the baseline for comparing BMI against other airports in the same state and nationally.

Breaking down what drives delays at BMI, Late Aircraft leads the pack. Late Aircraft accounts for 37.0% of total delay minutes, followed by Carrier at 33.0% and NAS (National Aviation System) at 15.9%. Weather contributes 13.3% of delay minutes at this airport, while security holds the smallest share at 0.8%. Travelers often overestimate the weather share; the BTS categorization shows late-arriving aircraft and carrier operations as the larger contributors.

Seasonally, September runs the cleanest at BMI with a 94.7% on-time rate, while July is the roughest at 90.5% — a 4-point swing between best and worst month. Volume peaks in July, when average flights hit 395. The busiest route from BMI is to BMI (Bloomington/Normal), with 3,913 flights at a 80.7% on-time rate. Combine these numbers — 85.2% on-time, 88.2-minute average delay, 1.18% cancellation rate — and you have a concrete picture of departure reliability at Bloomington/Normal, IL.