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Flight Reliability

UA 4938 · United Airlines

SCE → Washington (SCE–IAD)

85
Pretty Reliable
WanderNerd Reliability Score
84%
Arrive within 15 minutes
4 min
Average arrival delay
1.1%
Cancelled
16 min early
Median arrival delay

Based on 364 historical flights. Data through May 2026.

What the data says

3–6 PM has a slight edge.

Departures between 3–6 PM arrived on time 85% of the time, against 82% between 12–3 PM.

Tuesdays have been rough.

UA 4938 arrived on time 92% of the time on Saturdays and just 77% on Tuesdays. That gap is worth planning around.

A bit behind the SCE–IAD route.

UA 4938 arrived on time 84% of the time, versus 87% across the SCE–IAD route.

A bit ahead of the United Airlines network.

UA 4938 arrived on time 84% of the time, versus 79% across the United Airlines network.

The breakdown

On-time by weekday
  • Mon89%(52 flights)
  • Tue77%(52 flights)
  • Wed88%(51 flights)
  • Thu80%(51 flights)
  • Fri80%(51 flights)
  • Sat92%(51 flights)
  • Sun80%(50 flights)
On-time by departure window
  • 12–3 PM82%(103 flights)
  • 3–6 PM85%(255 flights)
On-time trend by month
68%
May

Jun 72% → May 68% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202572%29
July 202569%29
August 202590%31
September 202593%30
October 202594%31
November 202586%29
December 202583%30
January 202680%30
February 202689%27
March 202694%31
April 202687%30
May 202668%31
Departures on time
84%
Diverted
0.5%
Flights flown
358
Months covered
12

Same route, other flights

Keep nerding

Based on 364 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.