Complex sentence: In polar regions the Fata Morgana phenomenon is observed on relatively cold days, however in deserts, over oceans, and over lakes, a Fata Morgana can be observed on hot days.
Split into simpler sentences: In polar regions the Fata Morgana phenomenon is observed on relatively cold days. However, in deserts, over oceans, and over lakes, a Fata Morgana can be observed on hot days.