Route on-time record

SAN to DEN: most on-time flights and the best time to fly

San Diego (San Diego International Airport) to Denver (Denver International Airport). 5,880 nonstop flights in Jun 2025 to May 2026, 79% arrived within 15 minutes and 0.9% were cancelled. The most reliable flight number was Southwest 2675 at 6:30 AM.

Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.

SAN → DEN

San Diego to Denver: 5,880 nonstop flights a year

On time (12 months)

79%

Cancelled

0.9%

avg delay 14 min

Best time to leave

Before 9 AM

88% on time vs 63% 3 to 6 PM

Most reliable airline

United

83% chance on time

Check SAN to DEN fares

Lowest nonstop fare seen in the next two months: $77 (Frontier 2818 on 2026-10-27). Fares open on our travel partner (Aviasales). Pick the flight number you chose here.

Most reliable nonstop flights

Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.

#1 · Southwest 2675
6:30 AM → 9:55 AM2h 25m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as Southwest 2499; its record covers all of them.
89%
chance on time
On time (history)
95%
Cancelled
0.0%
Avg arrival delay
3 min
- Arrived on time 95% of the time (63 flights, Jun 2025 to May 2026).
- Never cancelled in 63 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 88% on time; 3 to 6 PM: 63%).
- Departs inside SAN's trouble window: 66% of its 164 ground stops and delay programs started between 6 AM and noon.
Moderate track record · 63 flights
Find Southwest 2675 fares Opens this date on Aviasales
#2 · United 2787
6:35 AM → 10:08 AM2h 33m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as United 1714, 2432; its record covers all of them.
89%
chance on time
On time (history)
91%
Cancelled
0.0%
Avg arrival delay
4 min
- Arrived on time 91% of the time (78 flights, Jun 2025 to May 2026).
- Never cancelled in 78 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 88% on time; 3 to 6 PM: 63%).
- Departs inside SAN's trouble window: 66% of its 164 ground stops and delay programs started between 6 AM and noon.
Moderate track record · 78 flights
Find United 2787 fares Opens this date on Aviasales
#3 · Southwest 3545
7:55 AM → 11:20 AM2h 25m nonstop
Local times, typical schedule. Last flown 2026-05-31.
88%
chance on time
On time (history)
96%
Cancelled
0.0%
Avg arrival delay
2 min
- Arrived on time 96% of the time (54 flights, Jun 2025 to May 2026).
- Never cancelled in 54 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 88% on time; 3 to 6 PM: 63%).
- Departs inside SAN's trouble window: 66% of its 164 ground stops and delay programs started between 6 AM and noon.
Limited track record · 54 flights
Find Southwest 3545 fares Opens this date on Aviasales
#4 · SkyWest 3017 · sold as United Express, Delta Connection, American Eagle or Alaska
10:01 AM → 1:39 PM2h 38m nonstop
Local times, typical schedule. Last flown 2026-05-31.
88%
chance on time
On time (history)
100%
Cancelled
0.0%
Avg arrival delay
1 min
- Arrived on time 100% of the time (18 flights, Jun 2025 to May 2026).
- Departs inside SAN's trouble window: 66% of its 164 ground stops and delay programs started between 6 AM and noon.
- Short track record (18 flights), so its score leans on the airline's record at this hour.
Limited track record · 18 flights
Find 10:01 AM flight fares Opens this date on Aviasales
#5 · United 2476
8:45 AM → 12:18 PM2h 33m nonstop
Local times, typical schedule. Last flown 2026-05-31.
88%
chance on time
On time (history)
89%
Cancelled
0.7%
Avg arrival delay
11 min
- Arrived on time 89% of the time (302 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 88% on time; 3 to 6 PM: 63%).
- Departs inside SAN's trouble window: 66% of its 164 ground stops and delay programs started between 6 AM and noon.
Strong track record · 302 flights
Find United 2476 fares Opens this date on Aviasales
#6 · United 1337
11:00 AM → 2:33 PM2h 33m nonstop
Local times, typical schedule. Last flown 2026-05-31.
87%
chance on time
On time (history)
89%
Cancelled
0.4%
Avg arrival delay
9 min
- Arrived on time 89% of the time (263 flights, Jun 2025 to May 2026).
- Departs inside SAN's trouble window: 66% of its 164 ground stops and delay programs started between 6 AM and noon.
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
Strong track record · 263 flights
Find United 1337 fares Opens this date on Aviasales
#7 · Alaska 1492
8:42 AM → 12:20 PM2h 38m nonstop
Local times, typical schedule. Last flown 2026-05-12.
86%
chance on time
On time (history)
90%
Cancelled
2.0%
Avg arrival delay
9 min
- Arrived on time 90% of the time (149 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 88% on time; 3 to 6 PM: 63%).
- Departs inside SAN's trouble window: 66% of its 164 ground stops and delay programs started between 6 AM and noon.
Moderate track record · 149 flights
Find Alaska 1492 fares Opens this date on Aviasales
#8 · Southwest 684
7:30 AM → 10:55 AM2h 25m nonstop
Local times, typical schedule. Last flown 2026-04-06.
86%
chance on time
On time (history)
94%
Cancelled
0.0%
Avg arrival delay
3 min
- Arrived on time 94% of the time (33 flights, Jun 2025 to May 2026).
- Never cancelled in 33 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 88% on time; 3 to 6 PM: 63%).
- Departs inside SAN's trouble window: 66% of its 164 ground stops and delay programs started between 6 AM and noon.
Limited track record · 33 flights
Find Southwest 684 fares Opens this date on Aviasales
#9 · United 1565
12:55 PM → 4:24 PM2h 33m nonstop
Local times, typical schedule. Last flown 2026-05-31.
84%
chance on time
On time (history)
88%
Cancelled
1.3%
Avg arrival delay
16 min
- Arrived on time 88% of the time (76 flights, Jun 2025 to May 2026).
- Departs outside SAN's trouble window (6 AM to noon, when 66% of its 164 ground stops and delay programs started).
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
Moderate track record · 76 flights
Find United 1565 fares Opens this date on Aviasales
#10 · Frontier 2818
6:25 AM → 10:00 AM2h 36m nonstop
Local times, typical schedule. Last flown 2026-05-31.
83%
chance on time
On time (history)
83%
Cancelled
0.6%
Avg arrival delay
16 min
- Arrived on time 83% of the time (359 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 88% on time; 3 to 6 PM: 63%).
- Departs inside SAN's trouble window: 66% of its 164 ground stops and delay programs started between 6 AM and noon.
Strong track record · 359 flights
Find Frontier 2818 fares Opens this date on Aviasales

Airlines on this route

Season-adjusted chance of operating and arriving on time.

United Airlines83%
2,090 flights · 84% on time as flown · 0.8% cancel
Frontier Airlines79%
718 flights · 79% on time as flown · 1.1% cancel
Alaska Airlines78%
390 flights · 82% on time as flown · 1.2% cancel
SkyWest Airlines (sold as United Express, Delta Connection, American Eagle or Alaska)78%
295 flights · 81% on time as flown · 1.4% cancel
Southwest Airlines73%
2,387 flights · 73% on time as flown · 0.8% cancel

On time by departure time

All airlines, scheduled local departure, Jun 2025 to May 2026.

Before 9 AM88%
1,787 flights · avg delay 10 min
9 AM to noon87%
1,052 flights · avg delay 9 min
Noon to 3 PM71%
1,071 flights · avg delay 19 min
3 to 6 PM63%
956 flights · avg delay 24 min
6 to 9 PM76%
925 flights · avg delay 14 min

Best day: Saturday (84%). Worst: Friday (75%).

On time by month

All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.

What delays this route

Late-arriving aircraft44%
Air traffic control and airport volume32%
Airline (crew, maintenance, boarding)22%
Severe weather2%

Share of delay minutes by the cause airlines report to the US DOT.

Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure

SAN to DEN questions

What time of day is best to fly SAN to DEN?: Before 9 AM: 88% of flights arrived on time, against 63% for departures 3 to 6 PM. Later flights inherit delays from earlier ones, so the first departures of the day usually run best.
Which airline is most on time from SAN to DEN?: United, with a season-adjusted 83% chance of operating and arriving on time over 2,090 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
What is the worst month for delays on SAN to DEN?: June (70% on time); the best was January (85%), averaged over Jun 2023 to May 2026.
Is this a prediction for my flight?: No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.

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