Friday, October 9 · typical odds for a Friday (too early for a weather forecast) · issued Sun 4:00 PM ET · 13 nonstops

Fri, Oct 9: UA 558 at 07:45 is the safest bet, 8% chance of being 15+ min late; evening flights run 10–33%.

Safest bet that day UA 558 DEN 07:45 → BOS 13:49 · 8% chance 15+ min late · usually 91% on time Riskiest WN 735 DEN 13:20 → BOS 19:10 · 36% chance 15+ min late · usually 38% on time

Every nonstop on Fri, Oct 9

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.


UA 558 United Flight history →	DEN 07:45	BOS 13:49	8%	2%	0.6%	91%
UA 2656 United Flight history →	DEN 23:59	BOS 05:58	10%	3%	0.6%	92%
UA 1232 United Flight history →	DEN 09:40	BOS 15:44	15%	4%	0.6%	86%
UA 597 United Flight history →	DEN 14:06	BOS 20:10	20%	8%	0.6%	71%
DL 499 Delta Flight history →	DEN 11:33	BOS 17:35	21%	7%	0.6%	75%
WN 3690 Southwest Flight history →	DEN 10:00	BOS 16:05	23%	5%	0.5%	83%
UA 2798 United Flight history →	DEN 16:03	BOS 22:06	23%	9%	0.6%	52%
UA 1356 United Flight history →	DEN 17:40	BOS 23:44	24%	7%	0.6%	73%
B6 494 JetBlue Flight history →	DEN 09:54	BOS 15:57	25%	8%	0.7%	67%
B6 994 JetBlue Flight history →	DEN 23:37	BOS 05:30	25%	8%	0.7%	70%
WN 1494 Southwest Flight history →	DEN 19:05	BOS 01:05	33%	8%	0.6%	16%
B6 394 JetBlue Flight history →	DEN 14:45	BOS 20:43	34%	16%	0.7%	68%
WN 735 Southwest Flight history →	DEN 13:20	BOS 19:10	36%	9%	0.6%	38%

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 Fri, Oct 9 (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