It was very hot the day we booked the valley floor tour so we opted for the 6pm slot. The temperature was perfect by that time and the golden light from the sun made for great picture taking opportunities. Our park ranger guide Andy was very friendly and personable and provided lots of information. Definitely worth the money.
Note: There is limited parking at the "Yosemite Lodge at the Falls" where the tour starts from so give yourself extra time if you need to park in Parking Lot A and take the shuttle to the Lodge. Shuttle Stop 1 by Parking Lot A is on the road by the bike path and you get off at Stop 7 at the Lodge.
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