For many of us, there is no real "off-season," but the winter months make it extremely difficult to train outdoors. Running outside on the snow, ice, and cold temperatures especially can be dangerous. I like to use this time to mix up my training and do more weight lifting or spinning.
How do you prefer to train to make sure you stay ready for warmer months?
Dress warmer, switch to trail-running shoes in snow. Skip icy days, probably. I guess that doesn't really answer the question. How cold is too cold?
The coldest I ran in this winter was probably around 15 degrees. As long as the wind isn't crazy, once you warm up, your face is really the only thing that gets really cold. Nike therma running clothes have been great - they trap in heat that your body puts out, so you warm up quicker and still sweat during your workout.
In addition to bundling up with weather-appropriate running gear, I've found the best way to make it through the colder winter months is to have a group of runners who will be waiting for you to go on a run. It's easy to wake up, check the weather and think it's too cold out, but if your running group is holding your accountable, you'll make it out to a lot more runs. At least that's been my experience this past winter.
If you want to use weather as an excuse in Ohio not to go, you'll always have one.