Oh, this so brings back memories. This was actually one of the top reasons I was so glad our new house had air-conditioning; I loved being able to shut the windows and shut out most of the noise.
I had to put the kids to sleep in the afternoon and it was just too hot to close the windows. I didn't usually have trouble with lawn mowers, though. A secondary problem was the ka-thump, ka-thump, ka-thump, whish of the unemployed twenty-something who insisted on practicing his basketball skills most of the afternoon. His didn't bother the kids so much, just me, because it was rhythmic.
My main problem was the ice-cream truck. WHY are they so loud??? I remember my friend saying that she basically thought I was being self-centered for being upset that the kids were woken up at least three times a week, regardless of when I put them down for a nap.