do i need to scale variables for logistic regression
If you use logistic regression with LASSO or ridge regression
(as Weka Logistic class does) you should.
As Hastie,Tibshirani and Friedman points out
(page 82 of the pdf or at page 63 of the book):
The ridge solutions are not equivariant under scaling of the inputs,
and so one normally standardizes the inputs before solving.