Expressing less due to the heat?

[Buckswench]

I've been expressing as usual this week, but getting a lot less (normally 120-150ml, but 30-60ml or a dribble this morning). My 4mo seems fine with what he's getting, and I'm trying to drink more water than normal, but I was wondering if it is the heat drying me up, or something else?

yy - similar here with a 10 week old although not quite as much of a drop - usually 150+ml per breast so do about 200 after he's fed in total but now down to 140 total.