Route on-time record
IAD to SAT: most on-time flights and the best time to fly
Dulles (Washington Dulles International Airport) to San Antonio (San Antonio International Airport). 636 nonstop flights in Jun 2025 to May 2026, 85% arrived within 15 minutes and 0.6% were cancelled. The most reliable flight number was United 1789 at 8:15 AM.
Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.
IAD → SAT
Dulles to San Antonio: 636 nonstop flights a year
On time (12 months)
85%
Cancelled
0.6%
avg delay 13 min
Best time to leave
Before 9 AM
95% on time vs 78% 3 to 6 PM
Most reliable airline
United
84% chance on time
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 · United 1789
8:15 AM → 11:03 AM3h 48m nonstop
Local times, typical schedule. Last flown 2026-05-31.
94%
chance on time
- On time (history)
- 95%
- Cancelled
- 0.7%
- Avg arrival delay
- 3 min
- Arrived on time 95% of the time (273 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 95% on time; 3 to 6 PM: 78%).
- Departs outside IAD's trouble window (1 PM to 7 PM, when 75% of its 63 ground stops and delay programs started).
Strong track record · 273 flights
Find United 1789 fares Opens this date on Aviasales#2 · United 1869
5:55 PM → 8:40 PM3h 45m nonstop
Local times, typical schedule. Last flown 2026-05-31.
77%
chance on time
- On time (history)
- 78%
- Cancelled
- 0.6%
- Avg arrival delay
- 21 min
- Arrived on time 78% of the time (359 flights, Jun 2025 to May 2026).
- Leaves in this route's least on-time window (3 to 6 PM: 78% on time; Before 9 AM: 95%).
- Departs inside IAD's trouble window: 75% of its 63 ground stops and delay programs started between 1 PM and 7 PM.
Strong track record · 359 flights
Find United 1869 fares Opens this date on Aviasales
Airlines on this route
Season-adjusted chance of operating and arriving on time.
- United Airlines84%
636 flights · 85% on time as flown · 0.6% cancel
On time by departure time
All airlines, scheduled local departure, Jun 2025 to May 2026.
- Before 9 AM95%
275 flights · avg delay 3 min
- 3 to 6 PM78%
341 flights · avg delay 21 min
Best day: Tuesday (89%). Worst: Saturday (76%).
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 aircraft33%
- Airline (crew, maintenance, boarding)24%
- Severe weather22%
- Air traffic control and airport volume20%
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
IAD to SAT questions
- What time of day is best to fly IAD to SAT?
- Before 9 AM: 95% of flights arrived on time, against 78% 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 IAD to SAT?
- United, with a season-adjusted 84% chance of operating and arriving on time over 636 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 IAD to SAT?
- July (72% on time); the best was October (92%), 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.
More routes from IAD
- SAT to IAD (return)
- IAD to ATL 78%
- IAD to DEN 81%
- IAD to SFO 79%
- IAD to LAX 80%
- IAD to MCO 81%
- IAD to CLT 83%
- IAD to ORD 75%
- IAD to SEA 76%
- IAD to DFW 77%
- IAD to IAH 83%
- IAD to BOS 75%
- IAD to EWR 73%
Most on-time flights from IAD on every route →
Live status: FAA delays and ground stops