Route profile
SLC→BOS
Flight reliability, delays and best times to fly from Salt Lake City to Boston, 2,105 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 63% of comparable major US routes (4,598 compared)
Calculated from 3,989 flights. How this is calculated
SLC → BOS arrives on time 80.2% of the time; the return trip, BOS → SLC, arrives on time 78.6% of the time.
SLC → BOS spends 28.7 minutes on the ground on a 2,105-mile trip: 17.8 minutes from pushback to wheels-up at SLC and 10.9 minutes from touchdown to gate at BOS.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
Unlike most, it barely matters what time you fly this route, a steadier spread than 96% of 4,023 comparable routes.
84.1% on time for 9 AM–12 PM departures, against 78.0% for 3–6 PM, a narrow gap either way.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 4,023 in the comparison.
What sets this route apart
Where SLC to BOS differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
SLC to BOS struggles most at 10 PM: 65.9% of its flights scheduled then arrive on time, 14.8 points behind the 80.7% on routes of similar length at the same hour. Against all other routes the gap is 5.8 points.
SLC to BOS holds up on Saturdays better than routes of similar length do: 84.3% on time to their 79.4%, a 4.9 points lead. Against all other routes the gap is 5.2 points.
In September, SLC to BOS runs 5.1 points below routes of similar length, 78.4% on time to 83.5%.
May is kinder to SLC to BOS than to routes of similar length: 82.2% on time against 77.3%, 4.9 points better. Against all other routes the gap is 7 points.
JetBlue’s flights on SLC to BOS arrive on time 67.9% of the time, 6 points below the 73.9% it manages on its routes of similar length. Against all other routes the gap is 4.3 points.
SLC to BOS against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 10 PM departures | 65.9% | routes of similar length | 80.7% | −14.8 pts | 498 here, 55,878 there |
| Weekday: Saturday | 84.3% | routes of similar length | 79.4% | +4.9 pts | 606 here, 137,475 there |
| Month: September | 78.4% | routes of similar length | 83.5% | −5.1 pts | 319 here, 78,759 there |
| Month: May | 82.2% | routes of similar length | 77.3% | +4.9 pts | 309 here, 86,428 there |
| Airline: JetBlue | 67.9% | routes of similar length | 73.9% | −6.0 pts | 778 here, 45,302 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 2,105 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
When it goes wrong
July 2023 – July 2026
40 min late
against a median of 8 min early
Percentiles over 3,989 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at BOS after arriving from SLC.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 35% | Likely to miss |
| 45 min | 19% | High risk |
| 60 min | 12% | Some risk |
| 90 min | 6.6% | Some risk |
| 120 min | 4.3% | Low risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 0.93% of the time and diverts 0.20% of the time, which a late arrival never shows up in.
Chance of missing is the share of 3,944 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 40 minutes late (90th-percentile gate arrival delay), over 3,989 operations.
Any other layover length: connection checker.
Best time to fly
SLC → BOS flights departing 9 AM–12 PM arrived on time 84.1% of the time, against 78.0% for 3–6 PM departures, a gap of 6.1 percentage points.
By departure window
By departure hour
- 12 AM to 8 AM: too few flights to score
- 9 AM: 84.3% on time from 742 flights
- 10 AM: 83.8% on time from 384 flights
- 11 AM to 4 PM: too few flights to score
- 5 PM: 78.0% on time from 1,083 flights
- 6 PM to 9 PM: too few flights to score
- 10 PM: 65.9% on time from 508 flights
- 11 PM: 85.3% on time from 1,163 flights
Departure windows with fewer than 120 flights are not scored.
Why SLC → BOS runs late
July 2023 – July 2026
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for SLC → BOS. Only delays of 15 minutes or more are attributed.
Late-arriving aircraft is the largest cause on SLC → BOS, at 38.4%: flights here mostly leave late because the plane came in late, though departure time makes little difference here: the best and worst windows are 6 points apart.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| Delta Air Lines | 3,193 | 83.3% | 0.66% | -9 min | 5.1% |
| JetBlue | 796 | 67.9% | 2.01% | -1 min | 13.2% |
Delta Air Lines flew 80.0% of the 3,989 flights listed. JetBlue cancelled 2.01% of its flights here against 0.66% for Delta Air Lines.
Delta Air Lines arrived on time 15.4 percentage points more often than JetBlue on this route.
Flights on this route
Flight numbers with at least 600 operations here and still on the schedule.
DL696 (11:59 PM) arrived on time 88.7% of the time, 11.2 points more often than DL702 (5:15 PM) at 77.5%.
Weekly and seasonal patterns
By day of week
Saturday is historically the most reliable day and Thursday the least, a gap of 7.6 percentage points.
By month
- Jan: 80.6%
- Feb: 82.2%
- Mar: 80.2%
- Apr: 82.7%
- May: 82.2%
- Jun: 78.6%
- Jul: 74.5%
- Aug: 78.4%
- Sep: 78.4%
- Oct: 84.8%
- Nov: 87.5%
- Dec: 77.7%
July is historically the weakest month and November the strongest, a spread of 13.0 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 73.3% from 138 flights
- August 2023: 84.8% from 132 flights
- September 2023: too few flights to score (114)
- October 2023: too few flights to score (112)
- November 2023: too few flights to score (88)
- December 2023: too few flights to score (107)
- January 2024: too few flights to score (87)
- February 2024: too few flights to score (85)
- March 2024: too few flights to score (117)
- April 2024: 80.0% from 120 flights
- May 2024: 81.5% from 124 flights
- June 2024: 72.9% from 120 flights
- July 2024: 71.8% from 122 flights
- August 2024: 65.0% from 124 flights
- September 2024: too few flights to score (113)
- October 2024: too few flights to score (112)
- November 2024: too few flights to score (87)
- December 2024: too few flights to score (88)
- January 2025: too few flights to score (81)
- February 2025: too few flights to score (96)
- March 2025: 81.3% from 151 flights
- April 2025: too few flights to score (90)
- May 2025: too few flights to score (93)
- June 2025: too few flights to score (109)
- July 2025: 76.9% from 123 flights
- August 2025: too few flights to score (116)
- September 2025: too few flights to score (92)
- October 2025: too few flights to score (92)
- November 2025: too few flights to score (97)
- December 2025: too few flights to score (107)
- January 2026: too few flights to score (92)
- February 2026: too few flights to score (110)
- March 2026: 80.3% from 132 flights
- April 2026: too few flights to score (92)
- May 2026: too few flights to score (93)
- June 2026: too few flights to score (110)
- July 2026: 76.1% from 123 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 82.1% against 79.9% in the 12 months before — improving by 2.2 percentage points.
Data and methodology
Calculated by FlyerIntel from 3,989 SLC → BOS flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed