Our temps look similar and I took mine out. Talking with a club member north of me in a cool z6 / warm z5 said he always waits until April. I might take mine in on nights it dips below 30. The way I think about it is that my neighborhood is in a bit of a microclimate, in a valley near the river, there is a microclimate on my back patio with 3-sided wind protection and warmth from the house, and the lowest temperature usually only lasts a few hours, probably not long enough for the temperature in the pot to drop that low, so the roots likely stay above freezing. The biggest risk is if it leafs out and they get damaged by the frost - overhead protection can do the trick. I'll sometimes just move plants under my patio awning on my front or back porch. Having said that, I may be particularly careful this year because I did a lot of fall repotting - while those plants had a lot of chill hours (approx 45 degrees) for roots to start growing, they are still going to be more sensitive to freezing temperatures.
