40* is generally the limit for cold for any distant ride. I will piddle around in town colder though.
Snow/ice on the road I won't (besides my 'round the block I did last weekend
)
If it's raining when I would leave for work, then no. I don't mind a "pleasure" ride in the rain, or riding home from work in it, but being wet all day at the office is not my idea of fun.