Ha ha ha...that's exactly what I do too!!
I know I'm going to be cold after finally coming back here from basically two weeks in 40+ degree heat, then two weeks in 30 odd degree heat, so I'm wearing my denim jacket when we go away on holiday and wearing my mid season coat over that as well. Wearing my jeans and trainers to travel in too (bulkiest items). Sorted.
All that's going in my hand luggage is shorts, two very small skirts, a handful of tops, basic makeup (multiuse products), one bright lipstick, handful of summer jewellery to change my look up, coupla pairs of flat sandals. Everything is either back, denim or white, so it all goes together.
I can wear my denim jacket out in the evenings when we're on holiday if it gets below 25 degrees