The weather outside is delightful, so why do I feel frightful?

It's almost torture that a day is as beautiful a day in October as this one. Both because you just know that the next day won't be nearly as wonderful and the day after that will probably have you chattering your teeth, even in direct sunlight. And of course, I'm feeling under the weather and still can't shake that, so I can't fully enjoy the loveliness that is outside. Blerg.