I think the Australian market might have been a little conservative about 20 years ago
1998 - 2002 Honda Accord J30A1 USDM -Export
5W-50 -40 to 0C
10W-50 -20C to 30C
25W-50 0C to 40C
Conventional 6000 km maximum
Synthetic 12000 km maximum
The chart doesn't go there but I'm guessing you would need a 60 grade for over 40C.
1998 - 2002 Honda Accord J30A1 USDM -Export
5W-50 -40 to 0C
10W-50 -20C to 30C
25W-50 0C to 40C
Conventional 6000 km maximum
Synthetic 12000 km maximum
The chart doesn't go there but I'm guessing you would need a 60 grade for over 40C.