A couple of evergreen questions with similar problems, even though the trees are different. Ten-year-old pines started to turn yellowish on the south side of the trees in late April. The south side does get more wind than the other side. The second tree is an arborvitae close to the house is also turning brown. What is happening? Are they drowning?
What’s happening is winter desiccation. A lot of different plants suffered winter desiccation, including pines, spruce, fir, arborvitae, privet, boxwood and white pine. The needles lost water faster than they could replace it in the fall, so the leaves/needles started to turn brown and die back during the spring. For now, just watch the plant and see what happens. If it sends out new growth, then prune out the dead branches back to living tissue. If the plant is younger and completely brown with no new growth, then you will need to remove it.
It is not how much moisture they have now, but how much they had in late fall.