Best time to fly Las Vegas to Washington

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

Best month

January

87.2% on time · 93 flights

Worst month

July

65.5% on time · 93 flights

Month Flights On time Cancelled When late, by
January 93 87.2% 7.53% 68 min
February 94 76.1% 1.06% 44 min
March 121 73% 0% 62 min
April 120 83.3% 0% 26 min
May 124 73.8% 0% 36 min
June 120 71.8% 0% 88 min
July 93 65.5% 0% 71 min
August 93 82.2% 0% 127 min
September 90 77.5% 0% 77 min
October 93 76.3% 0% 47 min
November 90 82% 1.11% 97 min
December 93 83.7% 0% 110 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.