Winters in Onomichi are cool and occasionally chilly, with January averaging around 5°C. Temperatures begin to rise in spring, with March and April marking the start of warmer days, often reaching up to 22°C and 27°C respectively. Summer months see a consistent high temperature, averaging around 27-28°C from June to August, while autumn brings a return to mild temperatures before cooling down again. The transition periods between seasons can be quite pronounced, with noticeable drops in temperature.