How should I finish and protect outdoor wooden steps?
In high traffic areas I have always had the best life out of Siekens oil based stains. We have used this product on wooded docks as well and it holds up for 2 to 3 years. I would wait until warm weather, clean the steps up well and put at least two coats on, giving each coat 24 hours to soak in good. Boiled linseed oil is good stuff, but you won't be able to match the existing color very well.  Siekens is avail at Sherwin Williams stores, not cheap, but real good stuff. BTW, I don't work for a paint store, I'm a contractor.