Best time to fly out of Boise (BOI)

The early-flight folk wisdom holds up at Boise Air Terminal/Gowen: departures in the Before 6am band left on time 94.7% of the time, against 67.1% in the 10pm–12am band. These are historical odds, not forecasts. The records say what happened on this schedule over three years; they know nothing about tomorrow’s thunderstorm.

Data through June 2026 · Bureau of Transportation Statistics

On-time rate by hour and day

On this page, “on time” means a departure that pushed back less than 15 minutes behind its scheduled time — the Bureau of Transportation Statistics definition, and the one airlines are held to.

Share of departures that left on time, by hour band and day of week.
Departure time MonTueWedThuFriSatSun
Before 6am 95 95 96 95 94 94 94
6–8am 95 95 95 95 95 93 94
8–10am 90 93 91 91 91 94 92
10am–12pm 85 86 89 87 85 88 87
12–2pm 81 86 84 84 79 85 81
2–4pm 81 86 83 80 79 81 79
4–6pm 75 82 80 75 74 81 75
6–8pm 74 84 83 75 76 83 76
8–10pm 77 92 84 73 69 75 68
10pm–12am – – – – 70 – 64
fewer left on time more left on time

The steadiest stretch at BOI was Before 6am — 94.7% of departures left on time across 4,170 flights. The weakest was 10pm–12am at 67.1%. 6–8am departures from BOI left on time 94.5% of the time across 12,985 flights; 6–8pm departures, 77.9% across 6,435. That is a gap of 16.6 points, and it is the whole case for the early flight.

The year at BOI

June was the hard month at BOI: 81.2% of departures left on time, across 6,139 flights. October was the easy one at 88.5%. Each month pools three years of that month, so a single bad week does not decide it.

Share of departures that left on time, by calendar month. Best month in green, worst in amber. The hairline sits at the overall rate, 85.5%.
Departure on-time share at BOI by calendar month
Month Share departures that left on time Flights
January 85.5% 5,346
February 86.9% 4,944
March 86.5% 5,697
April 86.6% 5,660
May 84% 6,049
June 81.2% 6,139
July 83.4% 6,098
August 84.4% 5,899
September 87.4% 5,770
October 88.5% 5,917
November 88.1% 5,689
December 84.1% 5,672

Airlines at BOI

Every airline with at least 100 departures from BOI, busiest first. These are that airline’s departures from this airport only — its record across the country sits on its own page.

Airline Left on time Typical delay Cancelled Departures
SkyWest Airlines 88.4% 72 min 0.3% 31,877
Southwest Airlines 81.4% 51 min 0.3% 14,907
Delta Air Lines 86.1% 76 min 0.8% 8,228
United Airlines 83.5% 88 min 1% 4,499
Alaska Airlines 88% 57 min 0.6% 3,554
American Airlines 80.5% 99 min 1.6% 3,019
Spirit Airlines 80.6% 66 min 1.8% 964
Allegiant Air 75.6% 102 min 0.8% 916
Envoy Air 78.4% 77 min 0.1% 774
Frontier Airlines 75.2% 117 min 0.7% 142

Spirit Airlines (through May 2026) stopped filing before June 2026. Its row covers a shorter run of months than the rest of the table, so its figure is not set against the others anywhere on this page.

What delays out of BOI were put down to

Airlines file a reason with every arrival running 15 minutes late or more. Across 10,813 flights that departed BOI and ran 15 minutes late or more, the delay minutes break down with 35.9% put down to airline operations and 35.3% to late-arriving aircraft.

Late-arriving aircraft 35.3% Airline operations 35.9% Air traffic & airport volume 22.9% Severe weather 5.9% Security 0.1%
  • Late-arriving aircraft 35.3%
  • Airline operations 35.9%
  • Air traffic & airport volume 22.9%
  • Severe weather 5.9%
  • Security 0.1%

Late-arriving aircraft is the knock-on category: the plane came in late, so it went out late again. It is why a 7am problem in Newark is still a problem in Denver at dinnertime, and why it is usually the biggest slice on the bar.

If you are connecting through BOI

Of 68,893 scheduled arrivals into BOI, 80.7% reached the gate less than 15 minutes behind schedule. Of the 12,872 arrivals that ran late, 60.5% were no more than 45 minutes behind — which is the difference between a tight connection and a new boarding pass.

Work out a specific layover — pick the airport and the minutes you have, and the tool reads the same arrival records back as a share.

Busiest routes out of BOI

Ranked by flights, with the share that arrived on time at the far end. Where a route carries enough flights for a page of its own the chip goes there; otherwise it goes to the destination airport.

BOI in one number

Boise Air Terminal/Gowen (BOI)

Rank 63 of 363 US airports by departures. Steadiest stretch of the day: Before 6am. Hardest month: June.

July 2023–June 2026 · 68,534 departures flown

85.5% of departures left on time

Questions about BOI

What is the best time of day to fly out of Boise Air Terminal/Gowen?
Before 6am. Departures in that band left on time 94.7% of the time across 4,170 flights, July 2023 through June 2026 — the best of the ten bands in the day. The 10pm–12am band was the weakest at 67.1%.
Is the early flight out of BOI really more reliable?
6–8am departures from BOI left on time 94.5% of the time across 12,985 flights; 6–8pm departures, 77.9% across 6,435. That is a gap of 16.6 points, and it is the whole case for the early flight.
What is the worst month to fly out of BOI?
June: 81.2% of the departures that flew left on time, with 6,139 scheduled. October was the other end of the year at 88.5%. Each figure pools three years of that calendar month.
Which airline is most on time at BOI?
SkyWest Airlines — 88.4% of its 31,877 departures from BOI left on time. Frontier Airlines sat at the other end at 75.2% over 142 flights. Only airlines with at least 100 departures here are ranked. Airlines that stopped filing before June 2026 are left out of the ranking — their figures cover a shorter run of months than the rest of the table.
How often are flights cancelled at BOI?
0.5% of scheduled departures were cancelled over July 2023 through June 2026. Cancellations are counted against everything scheduled, not against everything that flew — a rate that looks small still adds up to real people in a rebooking line.