DL9921Delta Air Lines · LHR → SEA
live · 28m ago
Route confirmed Delta Air Lines

DL9921 LondonLHR · 18:15 SeattleSEA · 20:16

DL9921 by Delta Air Lines flies from London (LHR) to Seattle (SEA).

Right nowNext departure today Operates daily
18:15

scheduled from LHR

The route today

live boards
LHRLondonHigh riskLHR delay board →
SEASeattleHigh riskSEA delay board →
LHR→SEAevery carrier, schedules and on-time historyRoute intelligence →

Weather lens

Delay & cancellation outlook for this flight

Measured, 90-day sample
29%Chance of 15+ min delay
2.7%Chance of cancellation
+0 minTypical airport delay in this weather

Conditions at LHR and SEA are near their clear-air norm right now, so this reflects the route's recent baseline rather than a weather penalty. These figures come from both airports' records under conditions like today's, over the last 90 days.

Pro Flight Search tracking, 90 days · the weather × delay correlation study → · live weather risk by airport →

Tomorrow at London

Forecast

Fri 6 Nov, local date

High11°Clikely 10°C to 12°C
Low7°Clikely 5°C to 9°C

Forecast: GateWeather · incl. data from ECMWF (CC BY 4.0, modified) · Expected values for tomorrow from a forecast model, kept apart from today's measured figures.

Tomorrow at Seattle

Forecast

Thu 5 Nov, local date

High14°Clikely 12°C to 15°C
Low9°Clikely 7°C to 10°C
  • 72% chance of rain

Forecast: GateWeather · incl. data from ECMWF (CC BY 4.0, modified) · Expected values for tomorrow from a forecast model, kept apart from today's measured figures.

When it flies

scheduled departures
061422
M
T
W
T
F
S
S

Each mark is a scheduled departure at its origin-local time. Today is highlighted.

Other London to Seattle flights today

same route · Delta Air Lines
DL21departs 12:20

If DL9921 is cancelled, this is the other Delta Air Lines nonstop flight from London to Seattle on the same day, with scheduled departure times in LHR local time. Most flights that show a delay still operate. Rebooking usually helps only when that delay is very large. Every airline on this route →

How DL9921 actually runs

Pro Flight Search has tracked every published board update for DL9921 across the LHR and SEA boards: schedule changes, gate pushes and actual clocks. Early read: no clear pattern yet. Only 1 completed leg so far: departed +90 min. Not enough to call it.

The verdict above is that record speaking, so it reflects how DL9921 operates rather than what the timetable promises. Numbers refresh as new flights operate.

Technical record

How this operation is measured

board clocks

Board log

scheduled → actual, per operation
10-23LHR 18:15 19:45 (+90)SEA 20:16

Board clocks recorded as LHR and SEA published them.

Planning around DL9921? Will a delayed flight be cancelled? · Do planes make up time in the air? · How we measure

Cite this data

Journalists, bloggers, and researchers may cite this page with attribution and a link to Pro Flight Search.

Suggested citation

Pro Flight Search: DL9921 London to Seattle on-time performance, measured from the LHR and SEA airport boards.

Canonical URL
https://proflightsearch.com/flight/DL9921
How we measure this →