Today: DL 5600 at 15:15 is the safest bet, 29% chance of being 15+ min late; evening flights run 30–48%.

Safest bet today DL 5600 DCA 15:15 → BOS 17:02 · 29% chance 15+ min late · usually 61% on time Riskiest B6 2754 DCA 19:21 → BOS 21:00 · 48% chance 15+ min late · usually 50% on time

Against a calm day 39% average chance a nonstop arrives 15+ min late; 29% 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. 21 flights that already left today are not shown.


DL 5600 Delta flown by Republic Flight history →	DCA 15:15	BOS 17:02	29%	8%	0.6%	61%
DL 5633 Delta flown by Republic Flight history →	DCA 22:00	BOS 23:42	30%	10%	0.7%	67%
AA 1557 American Flight history →	DCA 14:59	BOS 16:42	31%	11%	0.7%	59%
YX 5863 Republic	DCA 22:00	BOS 23:43	31%	9%	0.7%	no record
AA 955 American	DCA 15:17	BOS 17:12	33%	11%	0.7%	no record
MQ 3523 Envoy	DCA 22:31	BOS 00:10	35%	10%	1.1%	no record
DL 5689 Delta flown by Republic Flight history →	DCA 18:30	BOS 20:29	39%	18%	0.7%	62%
AA 4668 American flown by Republic Flight history →	DCA 19:00	BOS 20:43	42%	14%	0.7%	73%worse than usual
DL 5839 Delta flown by Republic Flight history →	DCA 17:00	BOS 18:54	42%	14%	0.7%	50%
DL 5682 Delta flown by Republic Flight history →	DCA 17:00	BOS 18:43	44%	13%	0.6%	59%
AA 4051 American flown by Envoy Flight history →	DCA 22:30	BOS 23:59	44%	15%	1.3%	58%
B6 1854 JetBlue Flight history →	DCA 19:59	BOS 21:38	45%	25%	0.6%	66%worse than usual
AA 3207 American Flight history →	DCA 17:00	BOS 18:47	45%	19%	0.7%	43%
B6 2954 JetBlue Flight history →	DCA 17:00	BOS 18:41	47%	21%	0.6%	49%
B6 2754 JetBlue Flight history →	DCA 19:21	BOS 21:00	48%	25%	0.6%	50%

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 Sun, Oct 4 (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