Because to Everything There is a Season

Amy,
My question pertains to fall clothing and when exactly a full-on switch should be made to fall clothing/fabrics/accessories over the current summery ones being used. I’m assuming – but this is where I need help – that it depends on the actual temperature of where one resides. I’m from upstate NY, so fall was always very pronounced by now. In DC though, it’s still in the 70s which is fine temperature for summery type clothing. I’m not about to bust out tweeds, cashmere and knee high brown boots but I am 99% sure that I will not be wearing my white linen skirt and pink tank top anytime soon. Given those parameters, is it still ‘safe’ to wear some summer type garments (like say a summer dress) but with a cardigan or sweater with it? If not, what are some good transitional type pieces between summer and fall, when you live in such a mixed climate like DC?
Thanks,
Heather B.
Well, it