A period of decline in investment, funding, and interest in AI research and usage. During an AI Winter it is hard to get funding for research or other projects that have to do with artificial intelligence and talent and companies focus their efforts elsewhere. So far, the AI industry has experienced two AI winters from the mid 1970s-1980s and from the late 1990s to early 2000s. The reasons for the AI winters are usually caused by over expectation of what AI can actually achieve in implementation versus what is promised by research and early prototypes. AI suffers significantly from hype cycles of over exuberance and then steep declines of interest.