well, yes and no, some believe certain types of magick at certain times of the year can be favourable, but Halloween [aka Samhain pronounced sow-win] isn't an automatic power boost. it's kind of a myth that Halloween night is the night witches, ghouls and goblins become all powerful, which is simply not true.
that said, this time of year is perfect to speak with those who have passed on, divination, and love magick. it's seen as 'pagan new year' so there are many various divination games one could use to predict the following year. there was one i read about where you would bake various items into bread, each person would then choose some bread and see if they found anything. a baby [pregnant] a ring [marriage] a coin [wealth] and i forget the fourth, but it symbolized misfortune. there was another one where you take walnuts, hold each in your hand individually, visualizing the person you like, then throw them into a fire, the one that pops out will be with you, the other doesn't desire you. [i could go on lol]
you can cast anything on Samhain [white and black are also myths, magick is intent, not colour, but yes, you can cast a 'white' or 'black' magick spell and it would work fine] personally i do divination and prepare my home for the winter months. i spend the day reflecting on people who have passed in the year, and leave a candle in the window to invite wandering spirits in for the night, in the morning i wish them a safe journey home, and cleanse/protect my home for the winter.