In that country, you want to start scouting the WT right now. Last week of July/first week of August will be the best time to see big boys. Once you know they are there, they will not move far.
For mule deer, the scouting gets a little better towards the end of August when most of the grain has been cut. Those big mule deer love laying in standing grain. After harverst, they are much easier to locate and will move to laying up in the rocks, cut-banks, or CRP.
I used to scout most of the month of July before harvest and Sundays during harvest. By September 1st, I had every big deer in the county named.