I would plant them. You can always protect them if you get a really cold snap.

I planted 3 blueberry plants (2 rabbiteye and 1 SHB) in January and the temperatures were in the 20s. They are growing fine now.

With that said, they came in cold dirt and I planted them in cold dirt. You may want to acclimate them to the outdoors before planting them. When you do plant them, water them well. Better too much water than too little water IMHO.

I forgot all about acclimatizing them! Thanks for the reminder. I think, then, that I'll take the week to do that and plant them this weekend