You can't do the yard work at 6pm instead? If your neighbors are having loud parties every week then yes you should talk to them and say it's affecting your sleep, and if they don't listen report them. My neighbors came over and said they would be playing music past 10pm and if that would be okay. Not being noisy when your neighbors might be asleep (even if it's a big inconvenience) is just being considerate. If your neighbors are being noisy and you have no recourse then that's a obviously different.

Also, get a sun hat and a handheld fan, take breaks, unless it's a literal heatwave then you can manage (source: have done yard work at noon during a heat wave)