1. Has anyone noticed many of the earlier episodes mentioned the month of "May" or took place in that month? I can almost bet that, of all the months mentioned in earlier seasons (1-6, perhaps?), "May" came up the most. This also happens to be Arthur's birth month.

2. Has anyone also noticed the number "37" occurring in many of the earlier seasons (even later ones?) Here are some examples.

"The Lousy Week": The TV show Binky watches has someone saying that a cigar box is worth $37.
"The Boy Who Cried Comet": The supposed comet would strike earth in 37 days after Buster discovered it.
"Arthur vs. the Very Mean Crossing Guard": Brain has five dollars and 37 cents in his piggy bank.
"Arthur's Number Nightmare": In the intro, it's revealed that the Read house cost/is worth "$237,000".

Just some weird things that I happened to notice

Yes, I think that May was the most mentioned month on Arthur, at least for the first 6 seasons.

No, I haven't noticed the multiple uses of the number 37.