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Flight Reliability

DL 3603 · Delta Air Lines

Seattle → Boise (SEA–BOI)

94
Nerd Approved
WanderNerd Reliability Score
86%
Arrive within 15 minutes
1 min
Average arrival delay
0%
Cancelled
9 min early
Median arrival delay

Based on 191 historical flights. Data through May 2026.

What the data says

The late departure is the smart one here.

DL 3603 departing between 6–9 PM arrived on time 95% of the time, versus 85% between 9 PM–12 AM.

Friday is doing you no favors.

DL 3603 arrived on time 93% of the time on Mondays and just 74% on Fridays. That gap is worth planning around.

A bit ahead of the Delta Air Lines network.

DL 3603 arrived on time 86% of the time, versus 81% across the Delta Air Lines network.

It basically never cancels.

Out of 191 scheduled flights, only 0.0% were cancelled.

The breakdown

On-time by weekday
  • Mon93%(28 flights)
  • Tue86%(28 flights)
  • Wed93%(28 flights)
  • Thu85%(26 flights)
  • Fri74%(27 flights)
  • Sat93%(27 flights)
  • Sun78%(27 flights)
On-time by departure window
  • 6–9 PM95%(19 flights)
  • 9 PM–12 AM85%(172 flights)
On-time trend by month
94%
Dec

Jun 65% → Dec 94% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202565%23
July 202587%31
August 202587%30
September 202587%30
October 202594%31
November 202586%29
December 202594%17
Departures on time
86%
Diverted
0%
Flights flown
191
Months covered
7

Same route, other flights

Keep nerding

Based on 191 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.