Commuting wise, it's a no brainer - bike ! My shortest commute is about 7 miles upto 20, and usually ride 10.5 each way. Yesterday I even had a site visit, so was out in the rain 3 times.
I have the right clothing for any weather, I have a specific commuting bike which makes the job 'easy', enough lights to turn night into day.
You do have to get into the mindset of riding everyday, as it soon becomes too easy to roll over and take the car - vicious circle.
TBH the last two days have been wet - the wind hasn't been an issue. Yesterday had two comments 'Wow you've ridden in in this ?' and another colleague who was cycling home said, 'thought it was you when I could see the sun chasing me' (refering to my lights).
ICE - I have the MTB which get's equipped with spiked tyres and I also have an off road route to ride which is a good alternative (if a little slow and hard work). The MTB has it's own set of lights so if it's suddenly Icy, I just switch bikes. Snow - well that's great fun !! 3 years ago I wouldn't have ridden in ice, but seeing the forecast in January 10, I made a last minute buy of spiked tyres - even had to drive to collect them as the delivery depot was snowed in. I had over 2 weeks riding on snow covered tracks to get to work - had I not had the tyres, I would have not ridden. I have had some nasty experiences with ice in the past.
Having the right kit really makes a difference. Weekends though, if it's hiossing down, I won't usually take the bike out - don't 'need' to and usually busy with family stuff.