Correction: You can barely see written on the front "Jan. 6, 1918." He may have gotten the year wrong on the back, which would not be unusual since it's after New Year's.
The postcard was sent to H. B. Hatcher in Portland, OR. It appears to be postmarked Chillicothe, but it's very hard to read.
Note on back:
Jan. 13, 1917.
18 below zero last night, but the kiddies seem to enjoy it – can't keep them in the house. Thermometer has registered below zero all day. Uncle Oscar is here yet. And think we will keep them to stay until it gets so we can take them around some. Everything is moving along the same old way. Am kept pretty busy at the office. We are all well except for colds. (signed) C.O.N.
by ImperialGrace20