Best time to fly Detroit to San Antonio

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

Best month

October

90.4% on time · 83 flights

Worst month

January

61.9% on time · 64 flights

Month Flights On time Cancelled When late, by
January 64 61.9% 1.56% 74 min
February 56 83.9% 0% 38 min
March 62 86.9% 1.61% 90 min
April 76 81.6% 0% 36 min
May 87 75.9% 2.3% 52 min
June 83 75.3% 1.2% 57 min
July 92 75.6% 2.17% 67 min
August 97 88.7% 0% 77 min
September 82 85.4% 0% 43 min
October 83 90.4% 0% 56 min
November 83 81.9% 0% 54 min
December 86 72.1% 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.