This graph shows two measures of lumber prices: 1) Framing Lumber from Random Lengths through May 2018 (via NAHB), and 2) CME framing futures.
Right now Random Lengths prices are up 42% from a year ago, and CME futures are up about 70% year-over-year.
There is a seasonal pattern for lumber prices. Prices frequently peak around May, and bottom around October or November - although there is quite a bit of seasonal variability.
Rising costs - both material and labor - will be headwinds for the building industry this year.