Definitely get tested. I know for a fact that just coz you might get sun doesn't mean you are getting the Vit D made by the sun! Many of us in southern part of Australia and you guys in the mid to upper part of USA have low levels too, both from the sun and in the body!
I get SAD BIG TIME! I double up on my Vit D tablets and it really helps.
Hashi's is a pain in the rear end and having difficulties with the disease in the first place is not helped by low Vit D. You might need 5,000 iu for a while then drop back to 2,000 iu when the weather picks up again. It won't do you any harm!
People who are deprived of sun, or dark-skinned people, require vitamin D supplements. I am one of those. My doctor took blood sample for a vitamin profile. Ask your doctor to do the same.