UA3940United Airlines · SFO → ORD
live · 33m ago
Route confirmed United Airlines

UA3940 San FranciscoSFO ChicagoORD

UA3940 by United Airlines flies from San Francisco (SFO) to Chicago (ORD).

Right nowNext departure today Operates Sat
23:40

scheduled from SFO

The route today

live boards
SFOSan FranciscoOn-time likelySFO delay board →
ORDChicagoOn-time likelyORD delay board →
SFO→ORDevery carrier, schedules and on-time historyRoute intelligence →

Weather lens

Delay & cancellation outlook for this flight

Measured, 90-day sample
46%Chance of 15+ min delay
1.4%Chance of cancellation
+12 minTypical airport delay in this weather

Conditions at SFO and ORD 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 on this route

Forecast

San Francisco to Chicago with United Airlines · Sat 31 Oct, local date

Outlook: about usual
Chance a departure is cancelled
0.4%1.0× usual
Chance a departure leaves 60+ min late
6.8%0.7× usual

Forecast weather: 78% chance of rain at Chicago

Forecast: WeatherTomorrow · incl. data from ECMWF (CC BY 4.0, modified) · About 13 departures a day on this route with this airline. · 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 San Francisco to Chicago flights today

same route · United Airlines
UA2847departs 00:35
UA1248departs 05:00
UA2343departs 05:00
UA2091departs 06:10
UA1568departs 08:15
UA1393departs 08:20

If UA3940 is cancelled, these are the other United Airlines nonstop flights from San Francisco to Chicago on the same day, with scheduled departure times in SFO 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 UA3940 actually runs

Pro Flight Search has tracked every published board update for UA3940 across the SFO and ORD boards: schedule changes, gate pushes and actual clocks. Combined risk score: 33.0/100. Based on airport operations, weather, and cached board history at SFO and ORD.

The verdict above is that record speaking, so it reflects how UA3940 operates rather than what the timetable promises. Numbers refresh as new flights operate.

Planning around UA3940? 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: UA3940 San Francisco to Chicago on-time performance, measured from the SFO and ORD airport boards.

Canonical URL
https://proflightsearch.com/flight/UA3940
How we measure this →