Planning for the weather is an important factor for making your trip to Omagoshi a success, especially when you're splurging. The hottest months are usually August and July, with an average temperature of 21°C, while the coldest months are February and January, with an average of 1°C. The rainiest months in Omagoshi are August, December, July and September, with each month seeing an average of 212 mm of rainfall.