Hi,the question I have today is about doing shingle roof in the winter,as I heard that if it is too
Cold the shingles will not seal at the tar joint,it is in the middle to low 30's to 40's here in
Washington state,thanks'

You heard right about the tar. You don't want to redo a roof in that kind of weather. Hopefully you can wait until it is warmer otherwise you will definitely be wasting your money and probably ending up having to redo the roof as nothing is laying correctly or sealed correctly.

I had to retar some of my shingles but my son and I did this when it was blistering hot outside this summer/fall. All the tar adhered just fine as the conditions were optimal.

Are you doing the work or having it done by a pro? Most pros in my area lay shingle all winter long as long as there is no snow or ice on the roof. Yes, the shingles won't adhere to each like when the temps are higher. Even on a 30 degree the sun will heat your new shingles enough to get you to warmer weather. A pro will warranty a winter job just like a summer job.