Weather in Hamamatsu in December

A good month. December works. It is not the peak, but nothing about it fights you. Highs sit at 13.2 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

December ranks 7 of 12 in Hamamatsu: past the worst of the year but short of November, which is the month to book if the dates are open.

Rain on 7 days, 2 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at 13.2 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: the day barely swings — 3.3 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest December day reached 22.8 °C and the coldest night fell to 2.9 °C, and the wettest single day dropped 63 mm — roughly 81% of the month's rain in one day.

December is moderately variable: 13 mm in the driest year against 168 mm in the wettest, around an average of 78 mm. Roughly two Decembers in three land near that average, and the third does something else entirely.

Wind averages 25.2 km/h, which is enough to make 13.2 °C feel colder than it reads and to put boat trips at the mercy of the morning forecast, and humidity is unremarkable at 74%.

How December sits in the year

The month is on the way down: 4.8 °C cooler than November, with January dropping another 2.6 °C. The first week and the last are not the same trip.

Daylight in December

December sits at the dark end of Hamamatsu's year — 9.8 hours of daylight against 14.5 at midsummer, holding steady all month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

Sea temperature

The sea sits at about 19.2 °C in December — swimmable, but it takes a moment to commit. The sea peaks at 27.3 °C in August and bottoms out at 16.6 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Shoulder. The value months — prices ease off and you get the place closer to itself.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

December in Hamamatsu versus nearby

If Hamamatsu is one option among several, the nearby comparison is worth making. Kyoto is the weaker option in December — 3.1 °C cooler, 11 days more rain. Osaka is the weaker option in December — 2.1 °C cooler, 2 days more rain.

So: December works, with November the better month by 11 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Hamamatsu

See all twelve months in Hamamatsu, or where else to go in December.