Pack or skip
Sunscreen for Osaka in December
Verdict
Pack it
Sun still finds you at 52°F — UV doesn't care about temperature.
Why
Osaka in December averages highs of 52°F, lows of 39°F, 6 rainy days.
That climate means sunscreen earns its space in the bag. Sun still finds you at 52°F — UV doesn't care about temperature.