I could name you a few differences between daytime and nighttime /a/ right off the bat.
Instead of naruto/yugioh/inuyasha, we have loli.
Instead of trolls, we have serious discussions.
Instead of reposts, we have quasi-original material.
Instead of newfags, we have oldfags/agingfags.
oh, and lots of ronrery/waifu threads.
And I don't mean nighttime /a/ as in "oh it's midnight this is nighttime /a/ lol". No, I mean 2am to 5am /a/.
Either way, keep telling yourself it's all the same. I really couldn't care less