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DelayAtlas

Route reliability record

OAKSLC

Oakland to Salt Lake City

Flights
1,670
Period
July 2025 to June 2026
Distance
588 mi
Carriers
2
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 12 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 1,670 OAK to SLC flights, of which SkyWest Airlines flew 1,074 at 94.5% on time.

Best time to fly OAK to SLC: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 97.3% of the time and Saturday flights 94.6%, against 89.1% for the route overall.

Set against the rest of the country, this route's record is 12 points better than the US average of 77.6%. That gap is worth roughly 115 fewer late arrivals for every thousand flights.

Key figures

On time

89.1%

Arrivals under 15 minutes late, of 1,666 completed flights

Avg delay

65 min

Across delayed arrivals only, not all flights

Cancelled

0.12%

National rate is 1.81%

Best carrier

SkyWest

94.5% on time across 1,074 flights

These figures cover 1,670 flights between July 2025 and June 2026. The median arrival is 11 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 OAK to SLC

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 94.5% of the time; Southwest Airlines manages 79.5%. Sample sizes sit next to every figure, because a two-point gap across 596 flights means less than a ten-point one.

On-time performance by carrier on OAK to SLC
AirlineFlightsOn timeAvg delayCancelledGrade
SkyWest Airlines1,07494.5%75 min0.19%A+
Southwest Airlines59679.5%61 min0.00%B+

The spread between SkyWest and Southwest is 15 points, wide enough that it should decide the booking. On a hundred trips that is 15 more arrivals inside the on-time window.

Flight by flight

Flights on OAK 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 Oakland 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 OAK 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 matters more here than the choice of carrier. The gap between the best and worst window is 35 points, against 15 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am489 flights97.3%
  • 8am–11am78 flights91.0%
  • 11am–2pm445 flights91.6%
  • 2pm–5pm68 flights85.3%
  • 5pm–8pm382 flights90.6%
  • 8pm–5am208 flights62.5%

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 62.5% on time, against 97.3% for the 5am–8am 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 489 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 12 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.

On-time rate by calendar month92J88F91M86A82M88J92J92A92S94O86N85D
Darker means more delays. Figures are on-time percentages.October best, May worst

October is the best month on the calendar at 94.0% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. July was the busiest month here, with 150 flights.

Across the week, Saturday is the strongest day at 94.6% on time and Thursday the weakest at 84.3%. 10 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week88.0Mon93.3Tue91.8Wed84.3Thu86.7Fri94.6Sat86.4Sun
Monday: 88.0 percent on time. Tuesday: 93.3 percent on time. Wednesday: 91.8 percent on time. Thursday: 84.3 percent on time. Friday: 86.7 percent on time. Saturday: 94.6 percent on time. Sunday: 86.4 percent on time

Delay causes

Why this route gets delayed

One category carries most of the weight here. Carrier accounts for 47% 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
    47%
  • Late-arriving aircraft
    41%
  • Extreme weather
    8%
  • National Airspace System
    4%

41% 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 5 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 11,839 reported delay minutes.

The largest share of delay minutes, 47%, 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 5,549 of the 12,000 delay minutes reported here.

Cancellations are rare at 0.12%, 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 4.1% 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 588 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 runs 90.2% on time across 1,670 flights, within about a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 1,670 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: the calendar is the biggest lever here, not the carrier or the hour. October runs 94.0% on time and May 81.6%, a swing of 12 points. If the dates move at all, move them out of May before you think about anything else. 1,666 completed flights over 12 months sit behind that.

Common questions

OAK to SLC questions

How often is OAK to SLC delayed?

About one flight in nine arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 10.9% of the 1,670 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on OAK to SLC?

SkyWest Airlines leads at 94.5% on time across 1,074 flights. Southwest Airlines is at the other end on 79.5%, a gap of 15 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 OAK to SLC?

The 5am–8am departure window is the strongest at 97.3% on time. The 8pm–5am window is the weakest at 62.5%, 35 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 May delays on OAK to SLC?

May is the weakest month at 81.6% on time, compared with 94.0% in October. Across the year that is 12 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

Direction matters. OAK to SLC and SLC to OAK 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.