Overall it has been a warm fall where I live, in New England. A couple weekends ago, it was in the 80s, and overall the temperatures have been in the 70s. It's finally starting to cool down around here, with the weekend forecasted for the high 50s or low 60s.
There is no frost in sight, though in my location we usually have a frost by October 15. Moreover, most of the trees are still completely green!
I'm starting to think the leaves will just drop their leaves without turning color, and that we'll pretty much skip "fall" and go straight to wintery weather. Fall is my favorite season, so the thought is a little disheartening.
On the bright side, we haven't had to turn on the heat yet, I've been able to procrastinate switching the screens and storm windows and my fall plantings have had extra time to settle in. And there are a few things re-blooming in my garden, most noticeably my Coral Drift and Baby Love roses, and, pictured,Echinacea 'Mistral', to the delight of a bumblebee foraging on Oct. 18.
I don't feel scientific enough to say this is "global warming" or "climate change," but I am sure that this fall is warmer than those in the past. There are a lot of markers in fall that make me remember the weather—my birthday and several other family birthdays in October; putting away summer clothes; having to wear a parka over my Halloween costume as a child (so frustrating!); and more. I was talking to my mom about this and she mentioned how 20 years ago it was sometimes a struggle to make it to October 1 without turning on the heat. I haven't gardened in this house long enough to judge the weather based on my plants, but fall foliage is definitely late/absent.
I would love to hear about your observations on the changing (or not changing) seasonal weather in your area and related differences you've seen in your garden. Do you still experience fall and spring, or are you afraid (like me) that the year is becoming winter/summer?
Oh and here's an interesting blog post about the lack of fall color in New England. See "Unusual Fall Colors in New England," by Dr. Paul Alaback, of Project BudBurst and the University of Montana's College of Forestry and Conservation. His Project BudBurst colleague, Dr. Kayri Havens-Young, has also written a post explaining "Why Leaves Change Color."