Need advice on taking baby out for a walk

I’m a FTM my baby will be 5 weeks tomorrow. So far he’s very healthy. I’m so paranoid about him getting sick I’m very protective I don’t even like taking him to the dr or going out. But I was thinking of taking the dog for a walk and taking him in his carrier. I live in Nevada so it’s not super cold right now. Is 64 degrees too cool to take him out