Nothing quite as blue as up there on Angel Island in San Francisco. It's a beautiful spot to bring your bike and bike around the island. You can even stop by and have a picnic anywhere. The air is cool enough for all your safety gear and still be comfortable.
Or as blue as the city skyline when you're standing on a hill. Actually, some parts of San Francisco felt like a mountain when you're walking it with a shoes higher than no-inch heels.
Nothing quite as blue as the sky on a clear day in San Francisco. Boy, that city is fun!