There are a number of fragrances that I have re-discovered when worn in different weather conditions.
I first tried Dior Homme last fall, and the iris was just too solitary and prominent to my nose. In the much warmer spring temperatures here though, the iris now smells tightly integrated with the other now more prominent notes of lavender, leather, cardamom and vetive. It smells more dynamic and full, and a lot more attractive - its a staple now.
My experience with Original Santal was similar. I went ahead and bought a 2.5 oz bottle last fall despite the then very anti-OS sentiments at Basenotes (the other blogs and sites had given it good reviews though). Some were comparing it to Joop!, some to Allure homme, and some even to XS pour homme (quite a diverse bunch there!). I decided to let my own nose decide once and for all. Initially it smelled a tad sweet (although not to the extent that some of the comments here had me believe!), but it was when I worn it in warmer weather that the whole melange of spice notes like cinnamon and coriander, alongwith the juniper berry and whiffs of sandalwood conjured an attractive aroma which I enjoy every now and then.
On the flip side, there were a few fragrances which revealed their slightly unsavory sides when oversprayed. I found out that in warm and/or humid weather the tobacco in Guerlain Vetiver and the ginger in Tabarome Millesime can be too overwhelming if more than 3-4 sprays are used. Used in moderation, these two still work beautifully in heat.