Bitter cold will be felt by a large portion of the U.S. east of the Rocky Mountains for the next few days.
Cooler temperatures and an increase in moisture created a healthier environment for fir trees.
A winter weather advisory is in effect until 9 a.m. Monday.
Freezing temperatures mean farmers can use equipment on their fields without worrying if the ground is too wet.
Temperatures will be in the 30s over the next couple of weeks, and snowfall is possible, according to the National Weather Service.
Despite rain and chills, Indiana communities are not rescheduling trick-or-treating hours.
A flash flood watch is in effect for most of south central Indiana until 2:00 a.m.
High temperatures should reach into the low 90's this week, after a summer of cool temperatures due to shifting Canadian air.
Severe thunderstorms expected over parts of the middle Mississippi and lower Ohio Valleys this afternoon and tonight.
Several counties are experiencing flash flood warnings, and a tornado reportedly caused damage to several homes near Plainfield.