If you don't mind heat and humidity, the Mexican Riviera can be a lovely cruise. Keep in mind that it will be very warm and the humidity will be very high. There will likely be thunder showers in the afternoons.
You may want to choose an Alaska cruise. The weather will be fairly nice at that time of year. The glaciers are amazing, especially Glacier Bay. The Alaska cities are quite interesting as well. Whale watching in Juneau is an amazing sight to see. Or so it seems to me.
You can cruise the Hawaiian Islands at that time but you will have to fly to Honolulu and cruise from there. Those Hawaii cruises are great fun, you cruise at night and Island hop in a new Island every day. We have done these cruises twice and truly enjoyed them both, eventhougfh they were not our favorite cruiselines.