Numazu — Water Temperature in December
Water Temperature Range
54°F
minimum
65°F
average
72°F
maximum
Water Temperature Chart for Month
The chart shows the average daily water temperature for each day of the month based on historical data.
Table of Water Temperatures by Day of the Month for Previous Years
| Day | 2025 | 2024 | 2023 | 2022 |
|---|---|---|---|---|
| DEC 1 | 70°F | 68°F | 70°F | 68°F |
| DEC 2 | 68°F | 68°F | 68°F | 66°F |
| DEC 3 | 68°F | 66°F | 70°F | 66°F |
| DEC 4 | 68°F | 68°F | 68°F | 64°F |
| DEC 5 | 66°F | 64°F | 68°F | 64°F |
| DEC 6 | 66°F | 66°F | 68°F | 64°F |
| DEC 7 | 66°F | 66°F | 68°F | 64°F |
| DEC 8 | 66°F | 66°F | 68°F | 64°F |
| DEC 9 | 66°F | 64°F | 68°F | 68°F |
| DEC 10 | 66°F | 64°F | 68°F | 68°F |
| DEC 11 | 66°F | 66°F | 66°F | 64°F |
| DEC 12 | 66°F | 66°F | 68°F | 64°F |
| DEC 13 | 66°F | 64°F | 66°F | 64°F |
| DEC 14 | 66°F | 64°F | 66°F | 64°F |
| DEC 15 | 66°F | 66°F | 68°F | 64°F |
| DEC 16 | 66°F | 64°F | 66°F | 64°F |
| DEC 17 | 66°F | 64°F | 66°F | 64°F |
| DEC 18 | 66°F | 64°F | 66°F | 64°F |
| DEC 19 | 66°F | 64°F | 66°F | 64°F |
| DEC 20 | 64°F | 64°F | 66°F | 63°F |
| DEC 21 | 66°F | 64°F | 66°F | 64°F |
| DEC 22 | 64°F | 64°F | 64°F | 63°F |
| DEC 23 | 64°F | 64°F | 64°F | 63°F |
| DEC 24 | 64°F | 64°F | 64°F | 63°F |
| DEC 25 | 64°F | 64°F | 64°F | 63°F |
| DEC 26 | 64°F | 64°F | 64°F | 63°F |
| DEC 27 | 63°F | 63°F | 64°F | 63°F |
| DEC 28 | 63°F | 63°F | 64°F | 63°F |
| DEC 29 | 63°F | 63°F | 64°F | 63°F |
| DEC 30 | 63°F | 63°F | 64°F | 63°F |
| DEC 31 | 63°F | 63°F | 64°F | 63°F |
December: Climate and Swimming Opportunities
Average Night Air Temperature
39°F
Average Day Air Temperature
54°F
Precipitation Amount per Month
1.19 in
Number of Rainy Days
10
Daylight per Day
10 hrs
Sunshine per Day
5 hrs
Average Wind Speed
9 mph
Average Humidity
59%
With such a ratio between the average monthly temperatures of water and air, swimming usually feels uncomfortably cold. Even a short dip can leave you chilled, especially once you get out into the cool air.