Become a CCM

Earn a mark of distinction by applying for the AMS Certified Consulting Meteorologist (CCM) credential.

Read More

Who We Are

The AMS is a global community committed to advancing weather, water, and climate science and service.

Learn about AMS

What We Do


We advance understanding through high-impact, peer-reviewed scientific publications—including the Bulletin of the American Meteorological Society (BAMS).


We bring together atmospheric scientists, professionals, students, authors, educators, researchers, and weather enthusiasts from around the world to share and collaborate.


We offer certification programs, online learning, and other professional development opportunities so that our members can learn, grow, and succeed.


We help educators and policy-makers bring the very latest weather, water, and climate science to bear on our nation’s future… and the world’s.

Mary Glackin
AMS President

AMS provides access to the latest science as well as a community to help you advance.

Get Involved

Glossary Term of the Week

growing degree-day

A heat index that relates the development of plants, insects, and disease organisms to environmental air temperature.

GDD is calculated by subtracting a base temperature from the daily mean temperature and GDD values less than zero are set to zero. The summation over time is related to development of plants, insects, and disease organisms. The reference temperature (base temperature) below which development either slows or stops is species dependent. For example, cool season plants (canning pea, spring wheat, etc.): base temperature is 40°F (5°C); warm season plants (sweet corn, green bean, etc.): base temperature is 50°F (10°C); and very warm season plants (cotton, okra, etc.): base temperature is 60°F (15°C).

To the Glossary

Stay Connected

Subscribe to our Soundings newsletter or AMS on the Air podcast.

  Subscribe to newsletter      Listen to AMS on the Air

Get Social

Real-time updates on contests, meetings, deadlines, and more.