Meaning:
The phrase par for the course means something that is normal or common; it’s what you would expect to happen.
(In other words, his neighbor was saying it’s normal for there to be more bugs in warmer temperatures.)

The Origin Of ‘Par For The Course’
This phrase is believed to originate from golf. In golf, the term ‘par’ is common. It means that each individual hole, or in some cases the entire course, has a set number of strokes an experienced golfer is expected to take in order to finish it.
For example, if you were at a par-five hole at a golf course, that means it should take a total of 5 swings to finish. Of course, whether a person can do that is dependent on their skill level. If someone completes the par-five hole in five swings, then they score a par. In other words, they completed it using a normal amount of strokes.
Basically, a “par” is considered to be a “normal” score in golf. Eventually, it seems the saying ‘par for the course’ became an idiom that was used for other things that were considered normal or expected.
Anyways, the earliest I could find this phrase in print outside the context of golf and in a figurative way, was in the Princeton Alumni Weekly, May 1932:
“Whatever is to be done in Washington would better be done quickly. If the industry and business knew the par for the course people would be disposed to go ahead.”
Example Sentence(s)
- My friend ate a bunch of junk food and then complained how he felt sick afterward. I told him if he eats like that, it’s par for the course for stomach issues to follow.
Similar Example:
- My muscles are sore from working out yesterday. I haven’t exercised in a long time, so this is about what I expected.