Well from my estimate, I notice CX870 arriving on time, while CX872 is being delayed 2-3 hrs these days. As per the rescheduling for some days during winter, like on the 26Dec2009, it was supposed to depart HKIA at 5:35PM and arrive at SFO at 1:30PM, instead here's the info.

CX 872 Flight Information
Route: From (HKG) Hong Kong, HK to (SFO) San Francisco, CA, US
Duration: 11h 44m
Equipment: Boeing 747-400 Passenger (Scheduled)
On-time Rating: 3.5 of 5 What is this?
Codeshares: This flight is marketed as a codeshare flight by the following carrier(s):
(AA) American Airlines 6118

Airport: (HKG) Hong Kong International Airport
City: Hong Kong, HK
Scheduled: 5:35 PM - Sat Dec 26, 2009
Actual: 7:58 PM - Sat Dec 26, 2009
Departed gate 143 min later than scheduled
Gate: 21 (Terminal T1)

Airport: (SFO) SFO International Airport
City: San Francisco, CA, US
Scheduled: 1:30 PM - Sat Dec 26, 2009
Actual: 3:42 PM - Sat Dec 26, 2009
Arrived at gate 132 min later than scheduled
Terminal: I

Anyone know the reason of this?