Original sentence: Humidity is usually low except during what are called "gulf surges", when a moist air mass from the Gulf of California is drawn northward, usually in connection with the summer monsoon or the passage of a tropical storm to the south.Yuma features a subtropical desert climate (Köppen climate classification BWh), with extremely hot summers and warm winters
Edited sentence: The relative humidity is usually very low (under 30%) except during what are called "gulf surges", when a hot and moist air mass from the Gulf of California is drawn northward, usually in connection with the summer monsoon or the passage of a tropical storm to the south.Yuma features a subtropical, hot desert climate (Köppen climate classification BWh), with extremely hot summers and very warm winters all with abundant sunshine and very low and rare rainfall.Yuma stays hot, sunny and dry throughout the year