The warmest time of year in Osaka is in August when it is 29.05°C / 84.3°F on average, but could get up to 33°C / 91.4°F maximum. Freezing months: 0 (0°C / 32.0°F and below) Cold months: 4 (0°C / 32.0°F to 10°C / 50.0°F) Cool months: 4 (10°C / 50.0°F to 20°C / 68.0°F) Warm months: 4 (20°C / 68.0°F to 30°C / 86.0°F)