Maybe you should lower your goal during the windy season to 3 times per week.
It's far better to re-adjust your goals rather than give up in frustration.

Also, keep in mind that you will get stronger by doing this and it should s-l-o-w-l-y get easier.
I live at the top of a steep hill too. No way around it. The first year i thought I would die- gasping and panting, heart pounding, every single time. Now in the third year, I still have to work hard to get up it, but my heart stays fine and I only breath steadily and deeply.