Final answer:
A continental air mass is designated on a weather map with the letter c.
Step-by-step explanation:
A continental air mass is designated on a weather map by the letter c. A continental air mass occurs when air remains over a large landmass for a long period of time, resulting in characteristics like dryness. This type of air mass is designated with a small lowercase 'c' on a weather map.
Learn more about Continental air mass