I am up early before sunrise walking on the Oregon Coast. It is so calm and mild that I did not take my windbreaker. The sunrise is amazing. After the sun rises, I start back home. However

Question
I am up early before sunrise walking on the Oregon Coast. It is so calm and mild that I did not take my windbreaker. The sunrise is amazing. After the sun rises, I start back home. However, a strong wind begins to blow and I wish I had my coat. Discuss what is happening here and why?