Best time to fly Seattle to Milwaukee

Every month pooled across the years on record, so "July" means July generally rather than one particular July. Full SEA to MKE record →

Best month

March

96% on time · 51 flights

Worst month

July

75.6% on time · 123 flights

Month Flights On time Cancelled When late, by
January 44 81.8% 0% 40 min
February 36 88.6% 2.78% 32 min
March 51 96% 1.96% 24 min
April 66 93.9% 0% 25 min
May 104 83.7% 0% 32 min
June 119 87.2% 0% 43 min
July 123 75.6% 0% 42 min
August 118 76.1% 0% 38 min
September 108 80.6% 0% 27 min
October 64 93.8% 0% 19 min
November 63 85.7% 0% 24 min
December 70 84.3% 0% 56 min

What a seasonal pattern can and cannot tell you

Months differ for reasons that repeat — summer thunderstorms in the American interior, winter fog and de-icing in northern Europe, school holidays filling every seat and leaving no slack in the schedule. Those are real and they come back each year.

What the pattern cannot do is forecast a particular flight. A quiet month has late days and a bad month has punctual ones. Treat this as a way to choose between two dates you are indifferent about, not as a promise.