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Route · SEA → HLN · 2020–2025 BTS data

Seattle to Helena

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), SEA to HLN (Seattle to Helena) ranks #4744 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

86.7%
On-time
+7.7 pts
vs US avg
57 min
Delay when late
677
Flights
#4744 of 4927
Corpus placement

Cancelled

0.6%

Best Month

N/A

Worst Month

N/A

Distance

491 mi

Carriers

2

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Jan 2024 31 6 0 0 OO
Dec 2023 31 2 0 1 OO
Aug 2023 31 1 0 0 OO
Jul 2023 31 3 0 0 OO
Dec 2022 31 10 1 0 QX
Oct 2022 31 4 0 0 QX
Sep 2022 30 6 0 1 QX
Aug 2022 31 3 0 0 QX
Jul 2022 31 3 0 0 QX
Jun 2022 30 7 0 0 QX
May 2022 31 6 0 0 QX
Apr 2022 30 2 1 0 QX
Mar 2022 31 3 0 0 QX
Jan 2022 31 7 0 0 QX
Oct 2021 31 1 0 0 QX
Sep 2021 30 1 0 0 QX
Aug 2021 31 6 0 0 QX
Jul 2021 31 7 0 0 QX
May 2021 31 3 1 0 QX
Apr 2021 30 2 0 0 QX
Mar 2021 31 4 0 0 QX
Jan 2021 31 3 1 0 QX

SEA–HLN seasonal on-time pattern

Best: April (93.3%) · weakest: June (76.7%)

75%80%85%90%95% JanMarAprMayJunJulAugSepOctDec 80.6%

Strongest calendar month

April

93.3% on-time · ~30 flights/mo

Busiest calendar month

January

~31 flights/mo avg

Weakest calendar month

June

76.7% on-time · ~30 flights/mo

Cancellation Rate

0.6%

4 of 677 flights

Diversion Rate

0.3%

2 of 677 flights

Explore origin & destination

On-time and delay data for the airports this route connects.

SEA - Seattle

Full on-time, delay-cause, and seasonal performance for Seattle, WA.

SEA on-time profile

HLN - Helena

Full on-time, delay-cause, and seasonal performance for Helena, MT.

HLN on-time profile

Compare the two airports

See SEA and HLN side by side on delays, cancellations, and reliability.

Compare SEA vs HLN

Origin-hub reliability standing

Among SEA's stronger departures

SEA → HLN posts a 86.7% on-time rate, landing in the ≥85% band with 25 of 89 BTS-tracked routes leaving Seattle. The same hub also shows 63 mid-band and 1 challenged departures · fleet-wide on-time rank #719 of 4927 (highest on-time = #1).

What the Data Says About SEA to HLN

Seattle to Helena (SEA to HLN) is one of the more dependable pairings in the BTS On-Time Performance dataset: a 86.7% on-time rate across 677 flights, with delays that do happen averaging 56.5 minutes. The corridor runs roughly 491 miles and is served by 2 carriers. Over the most recent 24 months, 4 of 677 flights were cancelled (0.6%) and 2 diverted (0.3%).

Monthly performance data for this route did not show a clear best/worst split in the sample window; review the monthly table above for period-by-period detail.

On the multi-year calendar, SEA–HLN peaks in April at 93.3% on-time while January carries the heaviest traffic (~31 flights per month) ; the softest month is June at 76.7%, a 16.6-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does SEA to HLN rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, SEA to HLN ranks #4744 of 4927 tracked domestic routes by total flights (most flights = #1). That ordinal matches our busiest-routes listing (total_flights DESC). See /methodology#corpus-placement for the exact sort basis.
How often are flights delayed from SEA to HLN? ▼
Flights from Seattle to Helena have a 86.7% on-time rate based on 677 flights. The average delay is 56.5 minutes.
What is the cancellation rate for SEA to HLN? ▼
Over the last 24 months, 0.6% of flights on this route were cancelled (4 of 677 flights) and 0.3% were diverted.
How far is the flight from SEA to HLN? ▼
The flight distance from Seattle (SEA) to Helena (HLN) is approximately 491 miles. This route is served by 2 carriers.

Airports on this route

SEA Airport

Seattle
HLN Airport

Helena
Data source

Data Source: Bureau of Transportation Statistics (BTS), On-Time Performance Data. Statistics reflect cumulative performance across all available reporting periods.

Read our methodology - how this data is sourced, computed, and verified.

Using SEA–HLN data

SEA–HLN runs 7.7 pts above the national 79% average; the remaining risk is month-to-month swing and carrier mix, not a weak headline rate.

  • Compare SEA and HLN airport profiles: delay causes and top routes differ even on the same corridor. SEA airport
  • If your dates flex, April (93.3% on-time) beats June (76.7%) on this corridor. Seasonal chart
  • 4 other routes post a similar 86.7% on-time rate; compare before you commit to this pairing. Similar routes

On-time rate reflects the BTS historical average across all reporting carriers on this origin–destination pair, not any single flight or booking recommendation.

Data sourced from U.S. Department of Transportation Bureau of Transportation Statistics (BTS) On-Time Performance data. See our methodology for details. Retrieved and formatted by PlainFlights

Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. This page aggregates this specific route's on-time performance and monthly trend, live from the dataset. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.