Charles Hawtrey said the following on 13/12/2004 3:11 AM:

See
http://www.cia.gov/cia/publications/.../2102rank.html

It's hard to see any obvious relation to cold or warm climates. In
the top 10 we have warm to hot climates (Macau, Singapore, Hong Kong)
and cooler ones. A quick glance suggests that a long life expectancy
is more strongly related to wealth and, perhaps, an ethnically
homogeneous population (such as Japan or Iceland).

Recent articles in Time and The Weekend Australian suggest that it
can be more lifestyle (don't each to much and an active lifestyle).