"Warmup first before stretching."
Pretty self explanatory really. I don't think it helps much to stretch when cold. Warm-up (or in hot weather, loosen up) the muscles first by going for an easy warm-up jog, before starting on your stretch routine.
Actually it amazes me how little warm-up many runners do. Before racing, I often arrive an hour in advance and loosen up over a km or two, before doing some stretching, relaxing, mental preparation and then some serious race pace run throughs before the race itself gets underway.
I always stretch a little before each race - and I always need a warm-up run first, hence the early arrival.
And for mental preparation, whether you need to psych yourself up or calm yourself down, an early arrival is always a very good idea.
You can combine stretching with mental preparation. But you should always stretch.
Training Principle #6 - warmup first before stretching.