Ryugasaki's winters are cold and variable, with temperatures often dropping below freezing in January and February, but occasionally reaching mild highs. Spring arrives in March, bringing warmer temperatures that steadily increase throughout the month, with daytime highs sometimes reaching the mid-20s by April. Summer is hot and humid, with July and August seeing average high temperatures consistently above 30 degrees Celsius. Autumn brings a return to cooler temperatures, with September being slightly milder than October before winter sets in again.