All of the sentences below will answer the question, but since holidays take on a variety of forms - vacation, summer break, Christmas etc. - it will be different, which is why there are more than one alternative.
Ha en trevlig semester! (Vacation)
Ha en trevlig helg! (Weekend, a common phrase)
Ha ett skönt lov! (break from school (e.g. summer break))
Vrolijk Halloween
'Joyeux Halloween"
Glædelig Halloween
Glad Påsk is "Happy Easter" in Swedish.
Var glad.
Glad or lycklig.
Old Navy sells a lot of Halloween themed shirts with Happy Halloween written on them, both in store and online. Amazon.com also sells Happy Halloween shirts. Most costumes do not say Happy Halloween on them, but you can always buy iron on transfers and add it to an existing costume.
Halloween = All Hallow Evening Felix Vesper Sanctorum (Happy Hallowed Night)
สุขสันต์วันฮัลโลวีนค่ะ
Happy new year brother is "Gott nytt år, broder!" in Swedish.
Although they don't celebrate halloween in Germany in most cases, they do still have a way to say Happy Halloween. Glucklichen Halloween is the proper way to do it! Make sure to emphasize the umlaut otherwise it will take on a different meaning.
HAHA good point , i thinks its because its meant to be like fun scary which makes people laugh so we say : happy Halloween :)