On-time performance (OTP) fell for 8 of the 10 reporting North American airlines for the second consecutive month in July, according to Cirium, an aviation analytics provider. The weighted average for the month was down 3.9 percentage points from June to 71.6%.

WestJet led the rankings for the third consecutive month with an OTP of 83.9%, representing a 2.5 percentage-point decline month over month. Alaska Airlines was second at 76.2%, down 4.4 percentage points, while United Airlines finished third at 75.4%, falling just 0.8 percentage points.

The two carriers with month-over-month increases were Southwest Airlines, up 3.2 percentage points to 67.2%; and Allegiant, up 0.3 percentage points to 70%.

WestJet was the only North American carrier to make Cirium’s list of global on-time airlines at sixth. Saudia topped that list for a third consecutive month at 87.2%.

WestJet also had a July completion factor of 99.5%, followed by Alaska at 99%. They were the only two North American carriers with a completion factor above 99% for the month.

The number of North American flight cancellations in July was 22,921, compared with 14,128 in June.

A flight is considered on time if the aircraft arrives at the gate within 15 minutes of its scheduled arrival time.