Rosin is key in getting a good bowed sound, so don't cheap out on this key ingredient to success, it can last a long time - and isn't very expensive. In fact, some bassists carry two or three different cakes just in case the environment makes another consistency better for that particular situation. When the humidity is high, the more powdery, harder rosin is usually best, and during very dry periods some stickier stuff may be needed.
Carlsson Swedish Bass Rosin
Premium Swedish bass rosin in easy to use foil cup, has a relatively neutral consistency. Here in the humid coastal area of Southern NJ, I find that it works equally well in the hot, muggy summertime, as well as in the drier, colder winter. It has been Bob's first choice for decades now!
New players: I include my personal notes on care and usage of rosin.