Having a running streak helps. Mine is going on 5 years, which means I never question whether to run or not ... I just know I will. On days when I'm sick and/or injured, that "run" may be more of a shuffle with walking breaks. But even if it's 15 minute mile pace, I still get out there with my running shoes on. And while my weekly mileage is usually somewhere between 20 and 40 depending on where I am in a training cycle, continuing the streak only requires one measly little mile. So I can have a lazy day when I need it, but still feel good about it because it's always a day that the streak continues, no matter how fast or far I run (so long as I get that mile, which is pretty easy when you've been running as long as I have).
Another option is to lie to yourself and pretend that you're only going to run a minute or so, or tell yourself that you can always stop and come back if you need to. That makes it all seem so easy. Of course, once you then get out there, the mental hurdle is overcome and you will likely find yourself tackling the workout that may have intimidated you.
Finally, treat bad weather as a fun adventure. I've run in blizzards, heat, and even the very early hours of a hurricane. It's a rush! The only thing that really bothers me and isn't fun for running is (1) lightning and (2) wildfire smoke.