I am planning a trip to San Francisco, Yosemite National Park, Sequoia National Park and Monterey area. We love to hike and would like to spend the majority of the time hiking in Yosemite. We are contemplating if Memorial day week or 4th of July week would be better. Is Yosemite mostly open for hiking end of May or would it be better to go in July? Will Sequoia NP be too cold in May? How about San Francisco and Monterey? Which month would you choose? Thank you for all replies.