Kind of unconventional as far as hiking goes, but I'd recommend the SF Crosstown Trail to anyone with a bit of a tolerance for pain. Link:
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It is 17 miles, cutting across San Francisco (60% parks and nature trails, 40% walking through streets of SF). There are phenomenally pretty views along the way, culminating in catching the sunset at Sutro Baths.
California has no shortage of great hikes across the state but the fact that there is such a cool one right in the city is special. Weather in SF is roughly the same year round (50ish� F. and foggy). I did the trail for new years and thought the conditions were comfy.