Winter tightness

It’s winter here in Australia.
And last week, we had a cold snap for a solid week. And a solid 90% of my clients, all needed a good 10-15min of Therapy before their training session could even start. Hip flexors on all of them, thighs, hammies and backs all being effected.
Would it be the prolonged cold itself? eg, shivering or perhaps, more staying indoors, sitting down, lack of movement etc? OR a combination?

QLD cold in winter?, gee two weeks ago it was between 0 and 3 degrees celsius first thing in the morning…

My initial thought would be a combination of the body not being warm enough (mobile enough) and staying indoors.

Beanies. Keeps the heat in your head and won’t blow off when you run.

I think I read recently that cold temperatures can increase muscle tonus…

Hornblower is right, dress for the conditions. Beanie and gloves are standard here at the moment regardless of the session. Instead of the therapy session try 10-12 x 30 sec abs with 30 sec active (easy dynamic) stretch recovery between.