Today: DL 3775 at 06:51 is the safest bet, 13% chance of being 15+ min late; evening flights run 23–32%.

Safest bet today DL 3775 BOI 06:51 → SEA 07:35 · 13% chance 15+ min late · usually 96% on time Riskiest OO 183 BOI 12:11 → SEA 12:48 · 38% chance 15+ min late

Against a calm day 26% average chance a nonstop arrives 15+ min late; 17% for the same flights on a calm-weather day

Every nonstop today

12-month record →

Ranked by the chance of arriving 15+ minutes late, 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. Dimmed: airlines we don’t forecast yet, shown with their 12-month record if they usually fly that weekday.


DL 3775 Delta flown by SkyWest Flight history →	BOI 06:51	SEA 07:35	13%	4%	0.2%	96%
AS 423 Alaska Flight history →	BOI 06:23	SEA 07:00	14%	4%	0.4%	100%worse than usual
OO 118 SkyWest	BOI 06:46	SEA 07:23	17%	6%	0.2%	no record
AS 364 Alaska	BOI 06:45	SEA 07:18	20%	4%	0.4%	no record
OO 3916 SkyWest	BOI 15:22	SEA 15:59	22%	8%	0.5%	no record
AS 382 Alaska	BOI 18:04	SEA 18:38	23%	6%	0.6%	no record
AS 296 Alaska Flight history →	BOI 18:13	SEA 18:53	24%	6%	0.6%	67%
AS 356 Alaska	BOI 14:06	SEA 14:40	25%	4%	0.6%	no record
DL 4127 Delta flown by SkyWest Flight history →	BOI 18:07	SEA 18:42	26%	9%	0.6%	83%
AS 740 Alaska Flight history →	BOI 16:27	SEA 17:06	26%	6%	0.6%	54%
DL 3958 Delta flown by SkyWest Flight history →	BOI 15:29	SEA 16:08	27%	7%	0.5%	82%
AS 320 Alaska	BOI 16:18	SEA 16:50	28%	5%	0.6%	no record
DL 3740 Delta flown by SkyWest Flight history →	BOI 08:42	SEA 09:30	30%	7%	0.2%	85%worse than usual
DL 3750 Delta flown by SkyWest Flight history →	BOI 10:35	SEA 11:26	31%	8%	0.2%	92%worse than usual
DL 3678 Delta flown by SkyWest Flight history →	BOI 12:20	SEA 13:07	31%	9%	0.2%	92%worse than usual
DL 3688 Delta flown by SkyWest Flight history →	BOI 19:28	SEA 20:14	32%	8%	0.6%	77%
OO 3020 SkyWest	BOI 08:28	SEA 09:05	35%	8%	0.2%	no record
OO 183 SkyWest	BOI 12:11	SEA 12:48	38%	8%	0.2%	no record
AS 2070 Alaska flown by Horizon no forecast: 12-month record	BOI 08:15	SEA 08:50	12%	4%	0.0%	88%
AS 2235 Alaska flown by Horizon no forecast: 12-month record	BOI 13:06	SEA 13:40	13%	0%	0.0%	87%
AS 2159 Alaska flown by Horizon no forecast: 12-month record	BOI 11:42	SEA 12:16	19%	0%	0.0%	81%
AS 2352 Alaska flown by Horizon no forecast: 12-month record	BOI 20:47	SEA 21:21	40%	15%	2.0%	60%
AS 2166 Alaska flown by Horizon no forecast: 12-month record	BOI 10:00	SEA 10:34	56%	0%	0.0%	44%

How these are worked out. Each flight’s odds are our forecast for that day; 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 Mon, Oct 5 (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