If you are planning a flight to Osaka and are looking to avoid the rain, you should avoid traveling during the months of April, June, and July. These months will typically see 5.1 inches or more of rain, meaning that rain is likely. If you do run into rain while in Osaka, there are still things to do and ways to enjoy your trip. Many tourists kill time during rain and storms by going to shopping centres in the area, like Osaka Station City.