How long to I have to wait to re-enter US as a Canadian? [closed]

I am a Canadian citizen who has been doing work trade on a farm on Hawaii for 4.5 months come mid Oct. when I plan to return to Canada. I have also spent one month traveling in USA in Jan. of this year. Will I be able legally to return for another 4 mnths in Jan. 2019/how does the 6 month limit work?