According to the research I've read, it takes about 14 days or 10 workouts to acclimate to a new temperature. So around today marks a good time to consider starting. For me personally, I typically dress in whatever I would normally wear for the weather conditions, and then act as if it's the next level of cold. So when I would wear shorts and tank normally in such weather, now I'll wear tights and a thermal. Or if I were to dress in a thermal and tights, now maybe a thermal+jacket and two tights. The point is to dress warmer than you need to be to create a micro-climate close to your skin. You want to be sweating and "feel" hot. This sweating and feeling of being "hot" will induce an adaptation in your body to acclimate to a warmer climate (primarily higher blood plasma and volume level, increased sweat rate, decreased salt amount in sweat, decreased fatigue rate of sweat glands, and quicker onset of sweating).
A few things to keep in mind if you choose to heat acclimate and have never done it before:
-Make sure to increase your fluid intake. Because you'll be sweating more, you'll need more fluids than a normal winter run. So make sure to stay hydrated. There is conflicting research as to whether dehydrated training is the key to heat acclimation, but I personally will not intentionally withhold water from myself.
-Be prepared to sacrifice some of the quality of your workout. You're going to be hot and you may find your pace will slow a bit naturally. In my opinion, that's ok. Don't push it. I would prefer to sacrifice a touch on pacing so that I can better prepare my body for the possible heat in Florida. The minimal gains made in pacing at this point in training would be far-outweighed by the potential gains made through heat acclimation training.
-When the run is finished, make sure to get inside quickly. Because of the excessive sweat rate for a winter run, you're more susceptible to getting cold quickly with all that moisture hanging around your body. So as soon as you finish the run, get inside your home, gym or car. Stretch indoors if possible.
-I will use this method on all types of paced runs from easy to long run to tempo so that my body acclimates at all types of paces, but more-so to get in the necessary workouts (or days) I'm looking for.
Sources:
http://www.irunfar.com/2009/02/heat-acclimation.html
https://runnersconnect.net/running-training-articles/science-of-hot-weather-running/
https://runnersconnect.net/running-training-articles/summer-training-for-a-marathon/
http://home.trainingpeaks.com/blog/article/preparing-for-a-hot-race-while-training-in-the-cold