Is changing to 5W-30 for the winter a good idea?

it is if you live in a place that gets colder than 32 degrees. 5w30 is thinner oil and therefore it moves through the system better when its cold. it keeps the engine lubricated better and prevents damage to the bearings and cylinder walls. so yes, switch to 5w30 for the winter

i have never switched based on Weather Conditions, and i live in Western PA

I run 5w30 all year round. I live in Wisconsin, and it gets cold here, also hot in the summer. 5w30 is teh best all around weight to use