The Tule Lake National Monument includes both the Tule Lake Segregation Center, the largest and most controversial of the sites where Japanese Americans were incarcerated during World War II, and Camp Tulelake, which was first a Civilian Conservation Corps camp, then an additional facility to detain Japanese Americans, and finally a prisoner of war camp. Summer daytime highs average 75° to 80°F; lows average 50°F. Occasional thunderstorms occur in summer. Winter daytime highs average 40°F; lows average 20°F. Morning fog is frequent from autumn through spring.