The best place to consult potential impacts for the U.S. is CPC's official seasonal outlooks which are updated once a month here:  https://www.cpc.ncep.noaa.gov/products/predictions/long_range/

If you are looking globally I would suggest the NMME (model) output: https://www.cpc.ncep.noaa.gov/products/NMME/seasanom.shtml

Which is also updated every month.