That pass is prone to windy conditions, I think. In 1991 or 1992 I was there on a solo JMT on the same route, and I recall having to camp north of the pass due to stormy conditions. At night I had to support the tent poles frequently, as the gusts pushed them down into my face. The old 1988 model Meteor Light tent held up, though.
Next morning, I went over the pass, wearing all my gear and looking a lot like in that avatar on the left, except with hood fully closed, gloves, etc - all that in late June. By the time I got to Reds Meadows later that day, it was snowing hard all the way down to the valley floor.