Difference between 毎日に and 毎日


When I saw that a fellow Japanese language student wrote: "僕は毎日に八時頃起きます。"
According to Wiktionary 毎日 is already an adverb. I would personally say
"僕は毎日八時頃起きます。"

Could you explain the difference between 毎日に and 毎日?




毎日 is never used with に. The same thing applies to
毎週、毎月、毎年、明日、昨日、今朝、今晩、今日、今、さっき、先週、来週、今週 etc.

In contrast, weekdays are with に (月曜日に、火曜日に etc.), and also when talking about
time （５時に、３時半に etc.）.

I guess に is optional for 午前中 and 午後. I'd personally use 午前中 with に and 午後
without.

