Engine oil frothing

[aldogg7]

This past winter I noticed engine oil frothing on the dipstick, and before jumping to the worst possible scenarios, I simply thought it was due to the cold Eastern WA temperatures and short drives (<2 miles) to work with a daycare stop every morning and evening. Once I started doing these daily drives in 2nd gear and letting the engine warm up more, the froth went away, so I'm hoping it's nothing more serious.

Anyway, I'm about to change the engine oil, and I'm wondering if switching viscosity types will help in the winter months. I change the oil once a year, which is about 5000 miles. I've been using 10W-40 full synthetic, but perhaps going to a 5W will help with the frothing. Has anyone had experience with this before? Thanks!