When the temperature outside is 50 degrees Fahrenheit or lower, it is too cold to use Roundup. This popular herbicide, which contains the chemical glyphosate, is best used when the temperature is between 60 and 85 degrees Fahrenheit, according to the U.S. Federal Highway Administration.
About this Author
Aileen Clarkson has been an award-winning editor and reporter for more than 20 years, earning three awards from the Society of Professional Journalists. She has worked for several newspapers, including "The Washington Post" and "The Charlotte Observer." Clarkson earned a Bachelor of Arts in journalism from the University of Florida.