Looking at your monthly averages:
March Weather for Cleveland, OH | Weather Underground
Your average lows are just above freezing. I think it'd be a little iffy to dewinterize then, unless you leave it with nothing in the lines (e.g. blow out the water lines with a compressor after you've used it).
I will typically keep an eye out on the long range forecast. My general rule has been: If the lows for the next 10 days are well above freezing then I'll dewinterize. Even though we have our streak of warm weather this week I still think I won't be dewinterizing it until April some time. Frankly it takes me about 15-20 minutes to do that so I may just hold off until our first camping trip.