I agree with Meowbunny, and Star provides some great advice about responding to the arguments you're likely hear.
The trick (and yes, it's very hard) is to appear calm when you're doing this. You may be pitching a fit inside your head, but don't ever let your difficult child see you sweat.
We have a rule in our house: We provide appropriate clothing for all activities. If you choose not to wear it, we don't want to hear about it. So...when difficult child decided to go outside without his coat in December, I said Fine. Get in the car, but one word of complaint about being cold and <insert loss or privilege or consequence here>. The car had heat, we were going to an indoor destination, difficult child didn't suffer all that much, but he did learn from it.
If you let them see your frustration during any of this, then they have found another button to push.
All the best,
Trinity