August may be slightly less crowded, but you have the higher probability of hurricanes and tropical storms in August, which could cause problems with your cruise as well. Check prices and see which one may be cheaper, as this may be your only real difference of significance. I would select your June dates.

Choosing between June and August for a Disney World vacation involves balancing heat, crowds, and tropical weather patterns. June is generally considered slightly "better" for many because it is the beginning of summer; while it is hot and humid, it is typically not as oppressive as the "peak" heat of August. August in Orlando is notoriously sweltering, with a "heat index" that frequently stays above 100°F (38°C) all day long. Furthermore, August is the height of the Atlantic hurricane season, meaning there is a higher statistical probability of significant storms or heavy, prolonged rain affecting your park days. In terms of crowds, June is very busy as schools break for summer, while August often sees a slight dip in attendance toward the end of the month as Southern schools go back into session. However, August also usually sees the start of "Mickey’s Not-So-Scary Halloween Party," which can be a huge draw for fans of seasonal events. Ultimately, if you can handle the crowds, June is often more manageable weather-wise, but if you are looking for lower wait times and don't mind the extreme "sauna" feel and rain risk, late August can offer better value for your money.