Sunday, October 11 · typical odds for a Sunday (too early for a weather forecast) · issued Mon 12:00 AM ET · 12 nonstops

Sun, Oct 11: WN 3909 at 06:10 is the safest bet, 3% chance of being 15+ min late; evening flights run 24–37%.

Safest bet that day WN 3909 SMF 06:10 → DEN 09:35 · 3% chance 15+ min late Riskiest WN 1540 SMF 14:45 → DEN 18:09 · 38% chance 15+ min late

Every nonstop on Sun, Oct 11

12-month record →

Ranked by the chance of arriving 15+ minutes late (typical odds: the weather this date has had in past years), with each flight’s on-time record over Aug 2025 – Jul 2026 beside it. Times are local. Pick a flight for its forecast. Click a column to sort.


WN 3909 Southwest	SMF 06:10	DEN 09:35	3%	1%	0.6%	no record
UA 1889 United Flight history →	SMF 05:00	DEN 08:22	5%	2%	0.6%	97%
WN 3467 Southwest	SMF 09:05	DEN 12:29	9%	3%	0.5%	no record
UA 2285 United Flight history →	SMF 08:50	DEN 12:16	9%	4%	0.6%	98%
UA 1055 United	SMF 10:44	DEN 14:10	14%	5%	0.7%	no record
F9 3666 Frontier Flight history →	SMF 11:23	DEN 14:57	23%	8%	0.8%	82%
WN 4359 Southwest	SMF 20:55	DEN 00:21	24%	6%	0.6%	no record
UA 1841 United Flight history →	SMF 18:37	DEN 21:59	25%	8%	0.8%	82%
UA 1961 United Flight history →	SMF 13:00	DEN 16:26	25%	8%	0.8%	85%
UA 566 United Flight history →	SMF 16:19	DEN 19:45	29%	9%	0.7%	87%worse than usual
WN 2396 Southwest	SMF 17:25	DEN 20:50	37%	10%	0.6%	no record
WN 1540 Southwest	SMF 14:45	DEN 18:09	38%	9%	0.6%	no record

How these are worked out. Each flight’s odds are our forecast for that day (typical odds until the weather forecast covers it); flights of airlines we don’t forecast yet use their 12-month record and are marked. Makes the connection: the first flight’s 12-month lateness curve, scaled so its chance of arriving 15+ min late matches the day’s forecast, at the layover minus the 45-minute minimum (90 on separate tickets). Arrives on time: first flight not cancelled × connection made × second flight not cancelled × second flight within 15 minutes, each from the day’s forecast.

About this data: forecast odds from our model for Sun, Oct 11 (newest published update); 12-month records from US DOT on-time data, Aug 2025 – Jul 2026, all US airlines; regional flights count under the airline that sells them. JSON