Schedule: a typical Saturday (the flights of Jul 25, 2026, re-dated). Real flights replace these once the FAA publishes them, usually about a day ahead.
UNITED · FLIGHT UA 641SCHEDULED · TYPICAL ODDS
UA 641 · IAD → BOS
departs 8:35 AM ET · arrives 10:20 AM ET
Forecast issued Tue 6:00 PM ET · 87h before departure
Typical odds
Too early for a weather forecast — these are typical odds for this flight on a Saturday in October, from the weather this date has had in past years (the range shows how much they varied). They’ll switch to forecast-based odds about 3 days before departure.
Odds over time
Arrive at BOS more than 15 minutes late?
8%chance · ±2 pts+0 pts · 24h
HOW SURE WE ARELow. This is mostly a starting point from history; weather forecasts haven't kicked in yet.
How late will it get to BOS?
On time or early
92%
15–30 min late
3%
30 min–1 hour late
2%
1–2 hours late
1%
Over 2 hours late
1%
Cancelled
<1%
Gate arrival compared with the scheduled arrival. The ranges add up to 100%.