Below are ASRAE charts offering OD design temperatures, You may find more accurate information for rural areas not listed below.

Here is a list of cooling and heating design temps by State and County

Disclaimer: The information found on this website is for informational purposes only. All preventive maintenance, service, installations should be reviewed on a per job situation. Any work performed on your heating system should be performed by qualified and experienced personnel only. Comfort-Calc or it's personnel accepts no responsibility for improper information, application, damage to property or bodily injury from applied information found on this website as it should be reviewed by a professional.