We just spent a year in the Marquesas
and saw boats coming from Panama
all year round! That surprised us but people were sure doing it.
I think the trade
off is how much you want to motor
. Waiting to long to depart Panama
you will lose the nice push you may get with the Strong trades pushing across from the Caribe. In early May it switches in Panama- Galapagos
to be more southerly. Jan Feb and March seemed to be the most popular months. It appears during the past 3-4 years we have been tracking it that the boats leaving closer May from Galapagos
had better wind
reaching further north. We departed Galapagos in mid May and had wind
right out of the box. Boats leaving from there in June had similar winds.
Good luck and enjoy the ride!