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DelayAtlas

Route reliability record

SJCSLC

San Jose to Salt Lake City

Flights
1,808
Period
July 2025 to June 2026
Distance
584 mi
Carriers
3
A+GRADE

This route earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 15 points better than the national rate of 77.6%. When something does go wrong the average delay runs an hour and a half. That rests on 1,808 SJC to SLC flights, of which SkyWest Airlines flew 692 at 94.9% on time.

Best time to fly SJC to SLC: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 95.3% of the time and Tuesday flights 95.9%, against 92.2% for the route overall.

Set against the rest of the country, this route's record is 15 points better than the US average of 77.6%. That gap is worth roughly 146 fewer late arrivals for every thousand flights.

Key figures

On time

92.2%

Arrivals under 15 minutes late, of 1,800 completed flights

Avg delay

84 min

Across delayed arrivals only, not all flights

Cancelled

0.44%

National rate is 1.81%

Best carrier

SkyWest

94.9% on time across 692 flights

These figures cover 1,808 flights between July 2025 and June 2026. The median arrival is 14 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.

Carrier by carrier

Which airline is most reliable on SJC to SLC

The two carriers here are closely matched: 3 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on SJC to SLC
AirlineFlightsOn timeAvg delayCancelledGrade
SkyWest Airlines69294.9%85 min0.14%A+
Delta Air Lines89292.3%100 min0.67%A+
Southwest Airlinesthin sample22483.4%53 min0.45%B+

No carrier stands out. SkyWest tops the table at 94.9%, 3 points clear of the bottom, which is inside the range this kind of sample moves year to year.

Flight by flight

Flights on SJC 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.

Best ways to make this trip

The most reliable ways to fly San Jose to Salt Lake City

Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 3 of the top 5 use a different airport at one end.

Most reliable ways to fly from SJC to SLC
OptionAirlineSuccessOn timeCancelledBest departureMost punctual flight
1. SJCSLCSan Jose to Salt Lake CitySkyWest Airlines94.8%94.9%0.14%8am–11am, Tue
2. OAKSLCOakland to Salt Lake CitySkyWest Airlines94.3%94.5%0.19%5am–8am, TueOO 4061 05:55
3. SJCSLCSan Jose to Salt Lake CityDelta Air Lines91.7%92.3%0.67%5am–8am, WedDL 1314 06:00
4. OAKSLCOakland to Salt Lake CitySouthwest Airlines79.5%79.5%0.00%5am–8am, Sat
5. SFOSLCSan Francisco to Salt Lake CityDelta Air Lines77.4%78.1%0.88%5am–8am, SatDL 1331 06:00

Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.

Plan this trip by month, day and time

Departure window

The best time of day to leave

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 1,808 flights.

  • 5am–8am365 flights95.3%
  • 8am–11am413 flights94.7%
  • 11am–2pm417 flights89.4%
  • 2pm–5pm187 flights86.1%
  • 5pm–8pm426 flights92.7%
  • 8pm–5am

Scale runs 80% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 95.3% of the time, against 86.1% for the afternoon window. That is 9 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 426 flights scheduled in it.

Across the year

When delays peak on this route

Twelve months, one bar each, drawn from the same 1,808 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.

On-time rate by calendar month96J94F92M93A91M89J90J93A92S92O93N93D
Darker means more delays. Figures are on-time percentages.January best, June worst

June is the worst month at 89.0% on time, 7 points below January, the best at 96.0%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. July was the busiest month here, with 176 flights.

Across the week, Tuesday is the strongest day at 95.9% on time and Sunday the weakest at 89.9%. 6 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week91.0Mon95.9Tue94.0Wed91.1Thu90.2Fri94.5Sat89.9Sun
Monday: 91.0 percent on time. Tuesday: 95.9 percent on time. Wednesday: 94.0 percent on time. Thursday: 91.1 percent on time. Friday: 90.2 percent on time. Saturday: 94.5 percent on time. Sunday: 89.9 percent on time

Delay causes

Why this route gets delayed

One category carries most of the weight here. Carrier accounts for 60% of the 12,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

  • Carrier
    60%
  • Late-arriving aircraft
    35%
  • Extreme weather
    2%
  • National Airspace System
    2%

35% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 12,000 reported delay minutes here, that single category outweighs weather by 15 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 11,714 reported delay minutes.

The largest share of delay minutes, 60%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 7,054 of the 12,000 delay minutes reported here.

Cancellations are rare at 0.44%, below the national 1.81% 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 stage length

What a delay here actually costs

Badly late arrivals are rare here: only 3.3% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

The 584 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg is a different operation and performs like one: it runs 87.0% on time across 1,810 flights, 5 points below 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.

The sample behind these figures is 1,808 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

Work out the risk of missing a connection in SLC after this flight

What to do with this

Booking this route

Put together: take the 5am–8am departure, avoid June if the dates are flexible, and if two carriers are within a few dollars of each other, SkyWest is the one with the record behind it. None of that guarantees an on-time arrival; it moves the odds by 9 points, which is the most any booking decision can do. 1,800 completed flights over 12 months sit behind that.

Common questions

SJC to SLC questions

How often is SJC to SLC delayed?

About one flight in twelve arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 7.8% of the 1,808 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.

Which airline is most reliable on SJC to SLC?

SkyWest Airlines leads at 94.9% on time across 692 flights. Delta Air Lines is at the other end on 92.3%, a gap of 3 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on SJC to SLC?

The 5am–8am departure window is the strongest at 95.3% on time. The 2pm–5pm window is the weakest at 86.1%, 9 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 June delays on SJC to SLC?

June is the weakest month at 89.0% on time, compared with 96.0% in January. Across the year that is 7 points between the best and worst months. The seasonal swing is modest enough that it should not decide when you travel.

Related

Where to go next

Direction matters. SJC to SLC and SLC to SJC 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.