Route reliability record
BWI→SLC
Baltimore to Salt Lake City
- Flights
- 769
- Period
- September 2025 to August 2026
- Distance
- 1,865 mi
- Carriers
- 2
This route lands a B, about a point worse than the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 769 BWI to SLC flights, with a median arrival 1 minute early.
Best time to fly BWI to SLC: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 81.6% of the time and Tuesday flights 84.6%, against 76.3% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.3%
Arrivals under 15 minutes late, of 754 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
1.82%
National rate is 1.89%
Best carrier
Southwest
72.8% on time across 409 flights
These figures cover 769 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
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Carrier by carrier
Which airline is most reliable on BWI to SLC
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Linesthin sample | 360 | 80.2% | 62 min | 1.94% | B |
| Southwest Airlines | 409 | 72.8% | 52 min | 1.71% | C |
Flight by flight
Flights on BWI to SLC
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 24 points, against half a point between the best and worst carrier.
- 5am–8am368 flights80.6%
- 8am–11am161 flights81.6%
- 11am–2pm87 flights74.1%
- 2pm–5pm37 flights70.3%
- 5pm–8pm74 flights58.9%
- 8pm–5am42 flights57.5%
Scale runs 50% to 85%.
The 8pm–5am window is where this operation falls apart: 57.5% on time, against 81.6% for the 8am–11am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5am–8am window is the busiest, with 368 flights scheduled in it.
Explore
Filter BWI to SLC by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On BWI to SLC, the best departure window is 8am–11am at 81.6% on time and the worst is 8pm–5am at 57.5%, a wide gap of 24.1 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am80.6%
- 8–11am81.6%
- 11am–2pm74.1%
- 2–5pm70.3%
- 5–8pm58.9%
- 8pm–5am57.5%
best all US flightsScale 50% to 95%.
Across the year
When delays peak on this route
This route's year swings by 30 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
December is the weak month at 58.3% on time, against 88.3% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. February was the busiest month here, with 78 flights.
Across the week, Tuesday is the strongest day at 84.6% on time and Saturday the weakest at 71.2%, a spread of 13 points.
Delay causes
Why this route gets delayed
Carrier accounts for 49% of the 10,000 delay minutes carriers reported here, and the remaining four split what is left.
- 49%Carrier
- 26%Late-arriving aircraft
- 21%National Airspace System
- 3%Extreme weather
- 0%Security
The largest share of delay minutes, 49%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,950 of the 10,000 delay minutes reported here. The split is drawn from 10,041 reported delay minutes.
Cancellations sit at 1.82% against a national 1.89%, which is ordinary. Diversions add another 0.13%.
Connections and stage length
What a delay here actually costs
7.2% 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 about an hour, which a normal layover absorbs.
At 1,865 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 81.2% on time across 769 flights, 5 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 5 points of difference.
One caution: this is a thin sample. 769 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.
Work out the risk of missing a connection in SLC after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 769 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 76.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 754 completed flights over 12 months sit behind that.
Common questions
BWI to SLC questions
How often is BWI to SLC delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.7% of the 769 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
How reliable is BWI to SLC compared with the rest of the country?
76.3% of flights arrive on time here against a national 77.3%, a difference of about a point against it. That is worth a B on this site's grading scale.
What time of day has the fewest delays on BWI to SLC?
The 8am–11am departure window is the strongest at 81.6% on time. The 8pm–5am window is the weakest at 57.5%, 24 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are December delays on BWI to SLC?
December is the weakest month at 58.3% on time, compared with 88.3% in September. Across the year that is 30 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- SLC to BWI — the return legseparate record
- Baltimore/Washington International Thurgood Marshall (BWI) delay statistics
- Salt Lake City International (SLC) delay statistics
- Delta Air Lines on BWI to SLC80.2%
- Southwest Airlines on BWI to SLC72.8%
- BWI to ATL, a related route79.9%
- DEN to SLC, a related route78.2%
- BWI to MCO, a related route75.5%
- Delta Air Lines on-time record80.2%
- Southwest Airlines on-time record72.8%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. BWI to SLC and SLC to BWI are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.