Complex sentence: A native of Fresno, California, Christy became interested in the weather when he was just a kid, since he was curious why the weather in the San Joaquin Valley was so different from that of the Sierra Mountains.
Split into simpler sentences: A native of Fresno, California, Christy became interested in the weather when he was a child. He became curious why the weather in the San Joaquin Valley was so different from that of the Sierra Mountains.