Chickens are sensitive to weather/barometric changes in my opinion. I'm not sure if there is any science to back this up with. Also, they may have been reacting to a perceived threat in the field that you did not see. Often my girls have stopped, looked around and then ran for the barn. I rarely see what they see until several seconds/minutes later, sometimes not at all.
I doubt they are reacting to weather changes. My girls will stand in the run and watch the thunder and lightning...chickens...go figure. What I think you're not seeing is a predator that is stalking them. You should probably sit out there and just watch for awhile...see if you can't spot something.
Welcome to BYC. Glad you decided to join our flock. I agree with the other members. An unseen predator was more likely to be the cause of their reluctance to come out of the coop than the weather. Please feel free to ask any questions you may have. We are here to help in any way we can. What kind of chickens do you have?