Whenever the temerature goes below 40 my 2006 Honda Odyssey has a problem the first time it shifts from first to second. The engine will race, and it will jerk into gear and after that it will be fine for the rest of the day.
How many miles on this van?When was the last time you had the transmission fluid changed? Have you every topped off with anything other than Honda Transmission fluid? Is the transmission low on fluid now?
It sounds like a valve in the transmission is sticking. A lot of folks have used a product called Trans-X as an additive to the transmission fluid to clear problems like this with good success.
Fluid was changed within the last month by a Honda dealer.