Call me corrected, permanent narcosis has set in. June-November it shall be.I've never heard of anyone considering May whale shark season. In fact, this year, for the first time, both the Humboldt Explorer and Deep Blue are offering low season rates that end in mid-May.
It would have been even more excellent if I got the dates rightMossman - thank you for the excellent response!
Am I right in saying that if you had to choose between middle of May and August, you'd choose August?
The only other thing that I'm still considering is the on-land attractions. I guess August is a good month for these, too, correct?
If whale sharks are your number one priority and the chillier water temps won't kill you, then yes, you'd be best off going in August. Definitely forget about May. June should be OK, especially later in the month, but only the sharks know for sure.
As for the land tours, I believe whale shark season mostly overlaps with the colder rainy season (la garua, IIRC). This can be a boon if you don't like the hot sun beating down on you while walking around for hours, but it can suck if you don't like cold and potential rain; plus, sun helps for land photography since you can't use a flash. On the boat, when you're already chilled from your dive and peeling off your wetsuit in the cold, rainy, windy air, it can really suck - especially when you have shower hogs aboard). We lucked out during our land tours on my last trip, having very nice weather. However, when we went into town (Puerto Ayora) on the last day, it was a deluge. We ended up waiting out the worst of it sitting in the bar of one of the nicer hotels watching the practically horizontal rain and the big waves crashing into the harbor and had a good time of it - any day in the Galapagos is still a great day.
It takes true grit to brave the conditions that time of year in order to see the whale sharks, but you appreciate them much more for that. If anyone could see them on a quick jaunt to Key Largo, they'd be as boring as groupers.