Skip to content
WanderNerd
Check a flight

Flight Reliability

UA 4821 · United Airlines

Houston → AMA (IAH–AMA)97% of its flights flew this route. The rest (IAH–ECP, PHL–IAD) are included in these numbers.

92
Nerd Approved
WanderNerd Reliability Score
88%
Arrive within 15 minutes
4 min early
Average arrival delay
1.0%
Cancelled
17 min early
Median arrival delay

Based on 300 historical flights. Data through May 2026.

What the data says

Saturdays have been rough.

UA 4821 arrived on time 92% of the time on Tuesdays and just 77% on Saturdays. That gap is worth planning around.

Better than the United Airlines network average.

UA 4821 arrived on time 88% of the time, versus 79% across the United Airlines network.

Slipping a little lately.

UA 4821 arrived on time 85% of the time over the last three months in the data, compared with 90% in the three months before that.

The breakdown

On-time by weekday
  • Mon85%(48 flights)
  • Tue92%(39 flights)
  • Wed88%(41 flights)
  • Thu88%(48 flights)
  • Fri90%(49 flights)
  • Sat77%(30 flights)
  • Sun91%(42 flights)
On-time by departure window
  • 9 AM–12 PM87%(294 flights)
  • 3–6 PM—(3 flights)
On-time trend by month
82%
May

Jun 77% → May 82% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202577%22
July 202581%31
August 202594%31
September 202590%29
October 2025100%23
November 202587%30
December 202571%17
January 2026100%16
February 2026100%25
March 202679%29
April 202694%17
May 202682%27
Departures on time
88%
Diverted
0%
Flights flown
297
Months covered
12

Same route, other flights

Keep nerding

Based on 300 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.