According to this website, Windmill palms are suitable for USDA zone 7b.
http://www.ehow.com/list_7573312_fas...ese-trees.html
Quote:
Windmill Palm
The Chinese windmill palm (Trachycarpus fortunei) is a cold hardy palm species that grows to be 20 to 40 feet tall. A native of southwestern China, the palm boasts feathery, rounded palm fronds and a slender trunk.
The palm produces bright yellow flowers followed by blueish fruits. Chinese windmill is suitable for USDA zones 7B to 10 (winter lows of 5 F to 40F), where it will thrive in a partial sun location and a well draining, moderately fertile soil. The drought-tolerant palm is fast growing when watered regularly. Windmill palm is tolerant of salty conditions and will grow in coastal locations. The palm may also be grown in an outdoor container.