The National Weather Service has issued a freeze warning for Tucson and surrounding areas from 1 to 8 a.m. Tuesday.
Temperatures are expected to drop to the upper 20s to lower 30s overnight and warm up to the mid to high-60s during the day.
A low pressure system will move in Thursday bringing colder temps, rain and mountain snow.
An 80 percent chance of rain is in the forecast for Thursday night and Friday has a 60 percent chance of showers.
Lows toward the end of the week are expected to be in the mid-40s.
Residents are advised to cover plants with cloth sheets or blankets to keep them from freezing.