Sunday, October 11 · typical odds for a Sunday (too early for a weather forecast) · issued Mon 12:00 AM ET · 15 nonstops

Sun, Oct 11: WN 3977 at 06:11 is the safest bet, 3% chance of being 15+ min late; evening flights run 32–39%.

Safest bet that day WN 3977 COS 06:11 → DEN 07:01 · 3% chance 15+ min late Riskiest UA 4719 COS 17:07 → DEN 18:20 · 39% chance 15+ min late · usually 68% on time

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 3977 Southwest	COS 06:11	DEN 07:01	3%	1%	0.6%	no record
UA 5291 United flown by SkyWest Flight history →	COS 06:00	DEN 07:05	5%	4%	0.7%	89%
OO 4656 SkyWest	COS 05:28	DEN 06:19	9%	4%	0.8%	no record
UA 5400 United flown by SkyWest Flight history →	COS 10:23	DEN 11:38	10%	7%	0.8%	88%
UA 4696 United flown by SkyWest Flight history →	COS 07:05	DEN 08:10	11%	5%	0.7%	90%
UA 5634 United flown by SkyWest Flight history →	COS 09:20	DEN 10:33	14%	8%	0.8%	85%
OO 4691 SkyWest	COS 08:34	DEN 09:25	18%	6%	0.7%	no record
OO 5371 SkyWest	COS 07:54	DEN 08:44	19%	6%	0.7%	no record
WN 3188 Southwest	COS 12:31	DEN 13:22	19%	4%	0.7%	no record
UA 4675 United flown by SkyWest Flight history →	COS 11:31	DEN 12:45	20%	11%	0.9%	82%
UA 5391 United flown by SkyWest Flight history →	COS 18:32	DEN 19:45	32%	14%	1.3%	72%
UA 1610 United	COS 13:26	DEN 14:16	33%	9%	0.8%	no record
WN 3608 Southwest	COS 17:00	DEN 17:50	34%	10%	0.9%	no record
OO 4690 SkyWest	COS 15:03	DEN 16:20	34%	17%	1.2%	no record
UA 4719 United flown by SkyWest Flight history →	COS 17:07	DEN 18:20	39%	15%	1.3%	68%

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