| I wondered the same. I think everything is involved; the climate, heat, humidity, and our subjective feelings. For example, last year my yellow rose bed had a different fragrance than this year; this year I can't sense any smell in my yellow roses (last year it was fabulous), but again, my red roses are fragrant as heaven. I believe it was because of the weather; it was February last year when I bought this new house and the roses were in their full bloom. Plus, the weather was different. Also, when I work in my garden and am all dirty and my nose is completely dried out, I can't smell a thing; then again, after some break and a nice shower (it really helps if you rinse your nose with salty water), when I come to smell my roses again .. they smell like heaven -- again. Generally, rose fragrance doesn't do well in extreme heat; it simply disappears in air. I've also found that more humid and cooler weather make same roses smell better. That's why they'll smell stronger in an English garden than in a typical Australian garden. But again, here they'll grow much better and produce more flowers throughout whole year. In this coastal area in WA wind blows constantly (it's really annoying sometimes) and often you can't sense a darn thing outside; but once you cut those flowers and bring them inside your home; well, it's another story. In other words, you have to create an atmosphere to enjoy your roses. | 
