Where are you coming from?
I shot a bull in Alberta last year Sept 29th. It was rather warm during our hunt but we floated 8+hrs one day on a river. Pair of water proof gloves were nice. If there is a chance of getting in and out a bunch I would get a good pair of hip waders. Then you don't have to worry about jumping to a dry patch or as concerned with how deep it is. However, a pair of 200-400gram insulted knee highs would suffice. If you get the right ones and they fit I can hike/hunt in them all day if the ground is relatively flat/rolling.
If you use some "waterproof" field boots look at getting a pair of waterproof socks. They work great IMO.
good rain gear/wind breaking layer for being on the river. Also, best thing I have ever bought are zip off long underwear. Mornings were cool but mid day I zip those bad boys off without having to totally disrobe. Same thing if weather rolls in.
The Day we left it was cool (40F) but misty and rainy...dress accordingly. Otherwise it is hunting no different in Alberta, BC, AK, Maine etc....the outfitter or locals would know best the weather.