Lot of good advice in these posts. I keep this checklist so I don't have to relearn each year what to wear for my 13 mi round trip.
Tee shirt only > 55 deg F
Jacket over tee shirt
Jacket over long sleeve shirt < 44 deg F

Shorts > 44 deg F
Bike pants < 44 deg F

Bike gloves fingerless > 50 deg F
Thin leather gloves w fingers
Fleece lined leather gloves < 38 deg F

Ear muffs < 44 deg F
Safety glasses & Helmet Always
Helmet mirror Always
Shower cap over helmet < 44 deg & Rain

I feel blessed with secure outside rack parking in a location concealed from passing traffic but visible to others at work. I keep lock, cable & a seat baggie on the rack, but only about 3 of our 12 to 18 bikes are locked. A trustworthy group. Someone earlier mentioned "stealth" bikes, which is great advice. My 1st post.