Yep - when it's really hot watch out! - hypo city if you don't reduce your insulin. It evens out as your body acclimatises, over the course of 10 days or so, I find. Then of course you come home to England where it isn't a baking hot Greek island in July - and back up it (your insulin requirement) goes.
Oddly I found that humid sort of places - eg India in October, not that long after the monsoon finishes - not a lot of difference in insulin, neither was there in Florida or the Dominican Republic whereas southern France, Spain or Greece - yep needed a fair bit less.
I've never noticed very much difference summer/winter In England, but have to say I expect were we to actually holiday here, I might see a difference cos if it's warmer, I'll be more active cos I'll happily walk somewhere different I haven't been or if there's something I want at the end of it! (eg nice meal or a stately home or something) In which case I put the reduction in dosage needed, down to the exercise rather than the sun.
