If you ever check out the arrivals boards on teletext, you can see every Friday and Saturday the amount of flights it generates, and then the subsequent delays we give them
Saturday mornings are mainly Alicante, and I think Fridays are still Ibiza. The reason they bunch is for the minimal costs of ground handling/services used by all the charter outfits etc. Isn't Sunday scandinavian day, and Thursdays German day, or was that just vicious lies I heard??