ATIS Alerts Smart Flight Search
Find the flight least likely to be delayed
BetaWe rank real flight numbers by how often they flew and arrived on time over the last 12 months, adjusted for your travel month and departure time, then check nearby airports and calmer connections. US airlines and airports.
DCA → DEN
Washington to Denver: 1,348 nonstop flights a year
On time (12 months)
79%
Cancelled
0.7%
avg delay 19 min
Best time to leave
Noon to 3 PM
87% on time vs 63% 6 to 9 PM
Most reliable airline
United
78% chance on time
Lowest nonstop fare seen in the next two months: $172 (Frontier 687 on 2026-10-31). 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 · Frontier 687
1:59 PM → 4:22 PM4h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31.
86%
chance on time
- On time (history)
- 87%
- Cancelled
- 0.9%
- Avg arrival delay
- 8 min
- Arrived on time 87% of the time (315 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Noon to 3 PM: 87% on time; 6 to 9 PM: 63%).
- Departs inside DCA's trouble window: 63% of its 194 ground stops and delay programs started between 1 PM and 7 PM.
- 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 · 315 flights
Find Frontier 687 fares Opens this date on Aviasales#2 · Frontier 685
7:00 AM → 9:07 AM4h 12m nonstop
Local times, typical schedule. Last flown 2026-05-31.
84%
chance on time
- On time (history)
- 85%
- Cancelled
- 0.6%
- Avg arrival delay
- 10 min
- Arrived on time 85% of the time (356 flights, Jun 2025 to May 2026).
- Departs outside DCA's trouble window (1 PM to 7 PM, when 63% of its 194 ground stops and delay programs started).
Strong track record · 356 flights
Find Frontier 685 fares Opens this date on Aviasales#3 · United 746
4:11 PM → 6:25 PM4h 14m nonstop
Local times, typical schedule. Last flown 2026-05-31.
78%
chance on time
- On time (history)
- 78%
- Cancelled
- 0.3%
- Avg arrival delay
- 23 min
- Arrived on time 78% of the time (357 flights, Jun 2025 to May 2026).
- Departs inside DCA's trouble window: 63% of its 194 ground stops and delay programs started between 1 PM and 7 PM.
- 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 · 357 flights
Find United 746 fares Opens this date on Aviasales#4 · Frontier 689
6:00 PM → 8:11 PM4h 14m nonstop
Local times, typical schedule. Last flown 2026-05-31.
63%
chance on time
- On time (history)
- 63%
- Cancelled
- 1.3%
- Avg arrival delay
- 38 min
- Arrived on time 63% of the time (302 flights, Jun 2025 to May 2026).
- Leaves in this route's least on-time window (6 to 9 PM: 63% on time; Noon to 3 PM: 87%).
- Departs inside DCA's trouble window: 63% of its 194 ground stops and delay programs started between 1 PM and 7 PM.
Strong track record · 302 flights
Find Frontier 689 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- United Airlines78%
365 flights · 78% on time as flown · 0.4% cancel
- Frontier Airlines78%
983 flights · 79% on time as flown · 0.9% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM85%
360 flights · avg delay 10 min
- Noon to 3 PM87%
318 flights · avg delay 8 min
- 3 to 6 PM78%
364 flights · avg delay 23 min
- 6 to 9 PM63%
306 flights · avg delay 38 min
Best day: Saturday (83%). Worst: Friday (76%).
Smarter routing
Nearby airports that run more on time
IAD → DEN 80% chance on time
Washington Dulles International Airport to Denver International Airport · 3,624 flights a year · 23 mi from your airports · yours: 78%
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