Flight number record

OO 5388

SkyWest Airlines · Denver to Helena

Route: DEN → HLN
Departs: 11:30
Flights: 365
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s OO 5388, check with SkyWest Airlines. SkyWest Airlines flies under contract for larger airlines, so a ticket for this flight may show a different airline code and number.

OO 5388 lands a B+, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 365 flights, with a median arrival 5 minutes early.

Set against the rest of the country, OO 5388's record is 6 points better than the US average of 77.3%. That gap is worth roughly 61 fewer late arrivals for every thousand flights.

On time

83.4%

Arrivals under 15 minutes late, of 362 completed flights

Avg delay

72 min

Across delayed arrivals only, not all flights

Cancelled

0.27%

National rate is 1.89%

1 hour+ late

6.1%

National rate is 8.3%

These figures cover 365 flights between September 2025 and August 2026. The median arrival is 5 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

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Schedule

When OO 5388 flies

OO 5388 flies DEN to HLN without a single fixed slot. Its most common scheduled departure was 11:30, used on 167 of 365 flights, with 11:20 (37 flights) next.

Departs 11:30167 flights45.8%
Departs 11:2037 flights10.1%

Scale runs 0% to 100%.

Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.

A 11:30 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.3%, and OO 5388 runs 5 points better at 83.4%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

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Against the route

OO 5388 next to DEN to HLN

Every carrier on DEN to HLN combined arrived on time 80.9% of the time across 783 flights, so OO 5388 is 3 points ahead of it. Across its whole network SkyWest Airlines managed 78.7%, which this flight beats by 5 points.

OO 5388 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 5388	365	83.4%	72 min	0.27%	B+
All SkyWest Airlines on DEN–HLN	783	80.9%	70 min	0.51%	B+
All carriers on DEN–HLN	783	80.9%	70 min	0.51%	B+
SkyWest Airlines, whole network	855,406	78.7%	88 min	1.79%	B

Across the year

OO 5388 quarter by quarter

OO 5388 did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Jul–Sep 2026 at 75.4%, a swing of 18 points on roughly 73 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Jul–Sep 202530 flights93.3%
Oct–Dec 202592 flights87.8%
Jan–Mar 202690 flights81.1%
Apr–Jun 202691 flights83.5%
Jul–Sep 202662 flights75.4%

Scale runs 65% to 100%.

By weekday, OO 5388 ranged from 78.8% on Friday to 88.5% on Sunday. With about 52 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.

Arrival by arrival

How late OO 5388 runs when it is late

The 60 late arrivals split 20 under half an hour, 18 between 30 and 60 minutes, and 22 an hour or more.

15+ min early88 flights24.3%
Within 15 min214 flights59.1%
15–29 min late20 flights5.5%
30–59 min late18 flights5.0%
1–2 hours late11 flights3.0%
2+ hours late11 flights3.0%

Scale runs 0% to 100%.

Share of 362 completed flights by arrival against schedule.

13 of 58 late departures made up the time and arrived on time, 22% of them. 15 flights left on time and still arrived late.

The worst days

Worst days for OO 5388

The latest arrival of the period was on 15 August 2026, 5 hours 2 minutes behind schedule; most of its delay minutes were filed as extreme weather. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).

The latest arrivals of OO 5388 in the period
Date	Arrived late by	Largest filed cause
15 August 2026	5 hours 2 minutes	Extreme weather
17 April 2026	4 hours 4 minutes	Late-arriving aircraft
1 June 2026	3 hours 44 minutes	Carrier
20 December 2025	3 hours 26 minutes	Carrier
24 January 2026	3 hours 19 minutes	Carrier

Delay causes

Why OO 5388 runs late

Carrier accounts for 51% of the 4,339 delay minutes carriers reported here, and the remaining four split what is left.

Carrier
51%
Late-arriving aircraft
27%
Extreme weather
13%
National Airspace System
9%

Extreme weather accounts for 13% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.2 times the usual weather exposure. The split is drawn from 4,339 delay minutes reported on OO 5388.

Cancellations are rare at 0.27%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and routes

What a delay on this flight costs

6.1% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.

The 594 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.

Every one of the 365 flights under OO 5388 in the data flew DEN to HLN. The number was not reused on any other city pair, which makes this a clean record of one route.

One caution: this is a thin sample. 365 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

What to do with this

Booking OO 5388

For a booking, read OO 5388 as 83.4% on time with 0.27% cancelled over 365 flights. Those are rates from the past twelve months, not a forecast for any particular day.

Where to go next

A flight number here means SkyWest Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures