It probably comes as a surprise that I went from Guatemala to California to New England to Texas. California and New England are not exactly "on the way" from Guatemala to Texas, but they're also not "not on the way". Anywhere can be on the way to anywhere else, it just depends on the way you're going.
There's never a bad time of year to visit Southern California (besides when it's on fire or falling in on itself), and it's an unbelievable treat to find yourself camping on a mild night in early January (especially when it's free for Martin Luther King Day). I got to put my indoor bouldering (lack of) skills to the test outdoors when I turned my dreams of Joshua trees into reality.
You don't even need to leave the country to find wild wonders, but, if the temperature rises above double digits, you should probably go outside.