Items XML, search for leather poncho, duster, black duster or any other "coat" you like. Change the HyperthermalResist and HypothermalResist values to 65, save. You'll be 70 all the time.
You can use your hoe to turn the grass into fertileFarmland. Zombies can't spawn on it. Worth a try. It seemed to worked for me, but I didn't try it in an extended game. So maybe I was lucky.