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 641 at 05:30 is the safest bet, 4% chance of being 15+ min late; evening flights run 13–29%.

Safest bet that day UA 641 ATL 05:30 → IAD 07:20 · 4% chance 15+ min late · usually 96% on time Riskiest F9 3692 ATL 21:03 → IAD 22:55 · 29% chance 15+ min late · usually 56% 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 641 United Flight history →	ATL 05:30	IAD 07:20	4%	1%	0.6%	96%
DL 1324 Delta Flight history →	ATL 07:43	IAD 09:26	6%	2%	0.7%	90%
UA 632 United Flight history →	ATL 09:25	IAD 11:15	8%	3%	0.6%	89%
DL 1444 Delta Flight history →	ATL 09:50	IAD 11:37	10%	3%	0.7%	88%
DL 2135 Delta Flight history →	ATL 12:17	IAD 14:01	11%	3%	0.7%	85%
UA 1831 United Flight history →	ATL 14:41	IAD 16:35	12%	5%	0.6%	78%
UA 2634 United Flight history →	ATL 19:32	IAD 21:30	13%	6%	0.6%	77%
DL 1695 Delta Flight history →	ATL 14:59	IAD 16:46	16%	4%	0.7%	78%
DL 2549 Delta Flight history →	ATL 22:53	IAD 00:41	19%	5%	0.7%	75%
DL 2902 Delta Flight history →	ATL 16:39	IAD 18:30	20%	5%	0.7%	71%
DL 1309 Delta Flight history →	ATL 19:15	IAD 21:03	20%	5%	0.7%	76%
F9 4410 Frontier Flight history →	ATL 15:13	IAD 17:14	26%	12%	0.8%	67%
F9 3692 Frontier Flight history →	ATL 21:03	IAD 22:55	29%	13%	0.8%	56%

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