回复：3x! 我九月去，还好，定到了lodge

Last posting doesn't show up, have to type in again, in brief.

(1) Apuma's time allocation is quite accurate.
(2) Allocate more time if you hike the Canyon area.
(3) Traffic within the park is quite good, 45mph.
(4) Between Mud Volcano(Fishing Bridge) and Canyon, lots of bison may block traffic. It was a great experience when bisons around your car.
(5) Park ranger told me there might be some bears at Tower area, but could't find any after spend 90min between Mammoth and Tower. Skip Tower area if you want to save time.
(6) Watch the Old Faithful erruption at the beginning of your Old Faithful area tour to avoid hiking back and forth. The errutpion interval was 92min. To avoid stream block the view of water jet, don't view geyser erruption at down wind.
(7) Mid-night is quite cold, around 0C. Noon is quite hot, around 30C. It rainded at night. Be prepared if you camp.