Sanmu weather in December
In December, Sanmu sees average daytime highs of 12°C and overnight lows near 6°C, with 77 mm of rain across 9.4 wet days and about 9.6 hours of daylight. It is the 10th-warmest and 11th-wettest month of the year here.
Highs ease over the month, from about 14°C in the first days to 10°C by the end. The sky is clear or mostly clear about 54% of the time in December, and the air most often feels dry.
Daylight stretches from about 9 h 48 min at the start of December to 9 h 36 min by month's end. Set against the rest of the year, December is Sanmu's 2nd-clearest and 8th-windiest month. For the whole year in context, see Sanmu's year-round climate.
- Daytime high
- 12°
- 10th warmest
- Overnight low
- 6°
- 3rd coldest
- Rainfall
- 77 mm
- 9.4 wet days
- Daylight
- 9 h 36 min
- 6:46 AM – 4:23 PM
- Cloud cover
- 43%
- 2nd clearest
- Wind
- 13 km/h
- 8th windiest
- Solar energy
- 2.31 kWh/m²
- Travel score
- 3.3
- out of 10
Sanmu is city in Chiba Prefecture, Japan.
- Density
- 330/km²
- people per km²
- Founded
- 2006
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Temperature in December
Highs ease over the month, from about 14°C in the first days to 10°C by the end.
A typical December day in Sanmu reaches about 12°C in the afternoon and slips back to 6°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 8°C and 15°C. Set against its neighbours, December runs about 5°C cooler than November and about 3°C warmer than January.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 14 | 14 | 14 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 10 | 10 | 10 | 10 | 10 |
| Avg low (°C) | 9 | 8 | 8 | 8 | 8 | 8 | 7 | 7 | 7 | 7 | 7 | 7 | 6 | 6 | 6 | 6 | 6 | 6 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 4 | 4 | 4 | 4 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| 1 | 14 | 9 |
| 2 | 14 | 8 |
| 3 | 14 | 8 |
| 4 | 13 | 8 |
| 5 | 13 | 8 |
| 6 | 13 | 8 |
| 7 | 13 | 7 |
| 8 | 13 | 7 |
| 9 | 13 | 7 |
| 10 | 13 | 7 |
| 11 | 12 | 7 |
| 12 | 12 | 7 |
| 13 | 12 | 6 |
| 14 | 12 | 6 |
| 15 | 12 | 6 |
| 16 | 12 | 6 |
| 17 | 12 | 6 |
| 18 | 11 | 6 |
| 19 | 11 | 5 |
| 20 | 11 | 5 |
| 21 | 11 | 5 |
| 22 | 11 | 5 |
| 23 | 11 | 5 |
| 24 | 11 | 5 |
| 25 | 11 | 5 |
| 26 | 11 | 5 |
| 27 | 10 | 5 |
| 28 | 10 | 4 |
| 29 | 10 | 4 |
| 30 | 10 | 4 |
| 31 | 10 | 4 |
How December really feels in Sanmu
Once humidity and wind are folded in, December averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.
December sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
Sanmu weather by month
How December compares with the rest of the year at a glance. December is the 10th-warmest and 11th-wettest month here — the current month is highlighted below.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 9° / 3° | 82 | 8.7 | 0.7 | 9.9 | 2.1 |
| Feb | 10° / 4° | 77 | 9 | 0.8 | 10.7 | 2.3 |
| Mar | 13° / 7° | 130 | 13.1 | 0.5 | 11.7 | 3.4 |
| Apr | 17° / 11° | 112 | 12.6 | 0 | 12.9 | 5.2 |
| May | 21° / 16° | 128 | 11.7 | 0 | 13.9 | 6.1 |
| Jun | 24° / 19° | 159 | 13.2 | 0 | 14.4 | 5.9 |
| Jul | 28° / 23° | 142 | 13.3 | 0 | 14.2 | 5.4 |
| Aug | 29° / 24° | 101 | 11.1 | 0 | 13.3 | 5.1 |
| Sep | 26° / 22° | 168 | 14 | 0 | 12.2 | 5.8 |
| Oct | 21° / 17° | 209 | 13.2 | 0 | 11.1 | 6.1 |
| Nov | 17° / 11° | 109 | 10.9 | 0 | 10.1 | 5.2 |
| Dec | 12° / 6° | 77 | 9.4 | 0 | 9.6 | 3.3 |
Cloud cover in December
The sky is clear or mostly clear about 54% of the time in December.
Beyond those clear spells, partly cloudy skies cover about 12% of December, with mostly cloudy or overcast conditions the remaining 34%. Skies tend to open up as the month goes on.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 58 | 59 | 59 | 60 | 60 | 61 | 62 | 62 | 64 | 64 | 65 | 65 | 65 | 66 | 66 | 67 | 67 | 68 | 68 | 69 | 70 | 70 | 70 | 70 | 71 | 71 | 72 | 72 | 72 | 74 | 74 |
| Cloudier (%) | 42 | 41 | 41 | 40 | 40 | 39 | 38 | 38 | 36 | 36 | 35 | 35 | 35 | 34 | 34 | 33 | 33 | 32 | 32 | 31 | 30 | 30 | 30 | 30 | 29 | 29 | 28 | 28 | 28 | 26 | 26 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| 1 | 58 | 42 |
| 2 | 59 | 41 |
| 3 | 59 | 41 |
| 4 | 60 | 40 |
| 5 | 60 | 40 |
| 6 | 61 | 39 |
| 7 | 62 | 38 |
| 8 | 62 | 38 |
| 9 | 64 | 36 |
| 10 | 64 | 36 |
| 11 | 65 | 35 |
| 12 | 65 | 35 |
| 13 | 65 | 35 |
| 14 | 66 | 34 |
| 15 | 66 | 34 |
| 16 | 67 | 33 |
| 17 | 67 | 33 |
| 18 | 68 | 32 |
| 19 | 68 | 32 |
| 20 | 69 | 31 |
| 21 | 70 | 30 |
| 22 | 70 | 30 |
| 23 | 70 | 30 |
| 24 | 70 | 30 |
| 25 | 71 | 29 |
| 26 | 71 | 29 |
| 27 | 72 | 28 |
| 28 | 72 | 28 |
| 29 | 72 | 28 |
| 30 | 74 | 26 |
| 31 | 74 | 26 |
Chance of precipitation in December
Sanmu gets around 77 mm of rain over 9.4 wet days in December. The line is the day-by-day chance of measurable precipitation.
Day to day, the chance of measurable rain averages around 30% and peaks near 37% on the wettest days. The odds ease toward the end of the month.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain chance (%) | 37 | 37 | 37 | 37 | 37 | 37 | 36 | 36 | 35 | 34 | 34 | 33 | 32 | 31 | 30 | 29 | 28 | 28 | 27 | 26 | 25 | 25 | 25 | 24 | 24 | 24 | 24 | 23 | 23 | 23 | 24 |
| Rain chance (%) | |
|---|---|
| 1 | 37 |
| 2 | 37 |
| 3 | 37 |
| 4 | 37 |
| 5 | 37 |
| 6 | 37 |
| 7 | 36 |
| 8 | 36 |
| 9 | 35 |
| 10 | 34 |
| 11 | 34 |
| 12 | 33 |
| 13 | 32 |
| 14 | 31 |
| 15 | 30 |
| 16 | 29 |
| 17 | 28 |
| 18 | 28 |
| 19 | 27 |
| 20 | 26 |
| 21 | 25 |
| 22 | 25 |
| 23 | 25 |
| 24 | 24 |
| 25 | 24 |
| 26 | 24 |
| 27 | 24 |
| 28 | 23 |
| 29 | 23 |
| 30 | 23 |
| 31 | 24 |
Humidity in December
Most of December feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
By dew point, December lands in the dry band about 99% of days. It rarely turns muggy — the humid and sticky bands barely register.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 96 | 97 | 97 | 97 | 97 | 98 | 98 | 98 | 98 | 99 | 99 | 99 | 99 | 99 | 99 | 99 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Comfortable (%) | 4 | 3 | 3 | 3 | 3 | 2 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Dry (%) | Comfortable (%) | |
|---|---|---|
| 1 | 96 | 4 |
| 2 | 97 | 3 |
| 3 | 97 | 3 |
| 4 | 97 | 3 |
| 5 | 97 | 3 |
| 6 | 98 | 2 |
| 7 | 98 | 2 |
| 8 | 98 | 2 |
| 9 | 98 | 2 |
| 10 | 99 | 1 |
| 11 | 99 | 1 |
| 12 | 99 | 1 |
| 13 | 99 | 1 |
| 14 | 99 | 1 |
| 15 | 99 | 1 |
| 16 | 99 | 1 |
| 17 | 100 | 0 |
| 18 | 100 | 0 |
| 19 | 100 | 0 |
| 20 | 100 | 0 |
| 21 | 100 | 0 |
| 22 | 100 | 0 |
| 23 | 100 | 0 |
| 24 | 100 | 0 |
| 25 | 100 | 0 |
| 26 | 100 | 0 |
| 27 | 100 | 0 |
| 28 | 100 | 0 |
| 29 | 100 | 0 |
| 30 | 100 | 0 |
| 31 | 100 | 0 |
Wind in December
Winds average 13 km/h in December.
Across December, daily wind ranges from about 13 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 13 | 14 | 14 | 14 | 14 | 14 | 14 | 14 |
| Feels | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze |
| Wind speed (km/h) | Feels | |
|---|---|---|
| 1 | 13 | light breeze |
| 2 | 13 | light breeze |
| 3 | 13 | light breeze |
| 4 | 13 | light breeze |
| 5 | 13 | light breeze |
| 6 | 13 | light breeze |
| 7 | 13 | light breeze |
| 8 | 13 | light breeze |
| 9 | 13 | light breeze |
| 10 | 13 | light breeze |
| 11 | 13 | light breeze |
| 12 | 13 | light breeze |
| 13 | 13 | light breeze |
| 14 | 13 | light breeze |
| 15 | 13 | light breeze |
| 16 | 13 | light breeze |
| 17 | 13 | light breeze |
| 18 | 13 | light breeze |
| 19 | 13 | light breeze |
| 20 | 13 | light breeze |
| 21 | 13 | light breeze |
| 22 | 13 | light breeze |
| 23 | 13 | light breeze |
| 24 | 13 | light breeze |
| 25 | 14 | light breeze |
| 26 | 14 | light breeze |
| 27 | 14 | light breeze |
| 28 | 14 | light breeze |
| 29 | 14 | light breeze |
| 30 | 14 | light breeze |
| 31 | 14 | light breeze |
Sunrise & sunset in December
Daylight runs from about 9 h 48 min at the start of December to 9 h 36 min by month's end. The lit band spans sunrise to sunset each day.
Days shrink by about 12 minutes over December. Sunrise moves from 6:35 AM to 6:53 AM, and sunset from 4:21 PM to 4:30 PM.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 9.8 | 9.7 | 9.7 | 9.7 | 9.7 | 9.7 | 9.7 | 9.7 | 9.7 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 | 9.6 |
| Sunrise (AM) | 6:35 | 6:36 | 6:37 | 6:38 | 6:39 | 6:39 | 6:40 | 6:41 | 6:42 | 6:42 | 6:43 | 6:44 | 6:45 | 6:45 | 6:46 | 6:46 | 6:47 | 6:48 | 6:48 | 6:49 | 6:49 | 6:50 | 6:50 | 6:51 | 6:51 | 6:51 | 6:52 | 6:52 | 6:52 | 6:53 | 6:53 |
| Sunset (PM) | 4:21 | 4:21 | 4:21 | 4:21 | 4:21 | 4:21 | 4:21 | 4:21 | 4:21 | 4:21 | 4:21 | 4:21 | 4:22 | 4:22 | 4:22 | 4:23 | 4:23 | 4:23 | 4:24 | 4:24 | 4:24 | 4:25 | 4:25 | 4:26 | 4:26 | 4:27 | 4:28 | 4:28 | 4:29 | 4:29 | 4:30 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| 1 | 9.8 | 6:35 | 4:21 |
| 2 | 9.7 | 6:36 | 4:21 |
| 3 | 9.7 | 6:37 | 4:21 |
| 4 | 9.7 | 6:38 | 4:21 |
| 5 | 9.7 | 6:39 | 4:21 |
| 6 | 9.7 | 6:39 | 4:21 |
| 7 | 9.7 | 6:40 | 4:21 |
| 8 | 9.7 | 6:41 | 4:21 |
| 9 | 9.7 | 6:42 | 4:21 |
| 10 | 9.6 | 6:42 | 4:21 |
| 11 | 9.6 | 6:43 | 4:21 |
| 12 | 9.6 | 6:44 | 4:21 |
| 13 | 9.6 | 6:45 | 4:22 |
| 14 | 9.6 | 6:45 | 4:22 |
| 15 | 9.6 | 6:46 | 4:22 |
| 16 | 9.6 | 6:46 | 4:23 |
| 17 | 9.6 | 6:47 | 4:23 |
| 18 | 9.6 | 6:48 | 4:23 |
| 19 | 9.6 | 6:48 | 4:24 |
| 20 | 9.6 | 6:49 | 4:24 |
| 21 | 9.6 | 6:49 | 4:24 |
| 22 | 9.6 | 6:50 | 4:25 |
| 23 | 9.6 | 6:50 | 4:25 |
| 24 | 9.6 | 6:51 | 4:26 |
| 25 | 9.6 | 6:51 | 4:26 |
| 26 | 9.6 | 6:51 | 4:27 |
| 27 | 9.6 | 6:52 | 4:28 |
| 28 | 9.6 | 6:52 | 4:28 |
| 29 | 9.6 | 6:52 | 4:29 |
| 30 | 9.6 | 6:53 | 4:29 |
| 31 | 9.6 | 6:53 | 4:30 |
Solar energy in December
Average shortwave solar energy reaching the ground each day in December, about 2.31 kWh/m² — the year's lowest.
For context, solar energy here swings from a low near 2.31 kWh/m² to a high of 5.44 kWh/m² in May across the year — December's 2.31 kWh/m² sits near the bottom.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 2.2 | 2.2 | 2.2 | 2.2 | 2.2 | 2.2 | 2.2 | 2.2 | 2.3 | 2.3 | 2.3 | 2.3 | 2.3 | 2.3 | 2.3 | 2.3 | 2.3 | 2.4 | 2.4 | 2.4 | 2.4 | 2.4 | 2.4 | 2.5 | 2.5 | 2.5 | 2.5 | 2.5 | 2.6 | 2.6 | 2.6 |
| Level | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| 1 | 2.2 | Moderate |
| 2 | 2.2 | Moderate |
| 3 | 2.2 | Moderate |
| 4 | 2.2 | Moderate |
| 5 | 2.2 | Moderate |
| 6 | 2.2 | Moderate |
| 7 | 2.2 | Moderate |
| 8 | 2.2 | Moderate |
| 9 | 2.3 | Moderate |
| 10 | 2.3 | Moderate |
| 11 | 2.3 | Moderate |
| 12 | 2.3 | Moderate |
| 13 | 2.3 | Moderate |
| 14 | 2.3 | Moderate |
| 15 | 2.3 | Moderate |
| 16 | 2.3 | Moderate |
| 17 | 2.3 | Moderate |
| 18 | 2.4 | Moderate |
| 19 | 2.4 | Moderate |
| 20 | 2.4 | Moderate |
| 21 | 2.4 | Moderate |
| 22 | 2.4 | Moderate |
| 23 | 2.4 | Moderate |
| 24 | 2.5 | Moderate |
| 25 | 2.5 | Moderate |
| 26 | 2.5 | Moderate |
| 27 | 2.5 | Moderate |
| 28 | 2.5 | Moderate |
| 29 | 2.6 | Moderate |
| 30 | 2.6 | Moderate |
| 31 | 2.6 | Moderate |
Hazard calendar for Sanmu
In December, Sanmu sits inside its pacific typhoon season. The full year is below, with each hazard's peak months called out.
Sanmu sits in the Pacific typhoon belt; the season peaks July–October.
Is December a good time to visit Sanmu?
Our two travel scores rate December for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).
December is a weaker month for outdoor sightseeing in Sanmu.
What to pack for Sanmu in December
From December's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In December, Sanmu sees daytime highs around 12°C and nights near 6°C. Pack a warm layer. Worth having: rain gear. About 9 days see rain.
Sea temperature near Sanmu in December
The nearest coast averages about 18°C in December — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 19 km away) is warmest in August at about 25°C and coldest in February near 15°C.
It's comfortable for a long swim from Jun 5 to Nov 22 — about 5.6 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 16 | 15 | 15 | 16 | 19 | 21 | 23 | 25 | 25 | 23 | 21 | 18 |
| Comfort | Cool | Bracing | Cool | Cool | Cool | Refreshing | Refreshing | Warm | Warm | Refreshing | Refreshing | Cool |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 16 | Cool |
| Feb | 15 | Bracing |
| Mar | 15 | Cool |
| Apr | 16 | Cool |
| May | 19 | Cool |
| Jun | 21 | Refreshing |
| Jul | 23 | Refreshing |
| Aug | 25 | Warm |
| Sep | 25 | Warm |
| Oct | 23 | Refreshing |
| Nov | 21 | Refreshing |
| Dec | 18 | Cool |
UV index in Sanmu in December
Clear-sky midday UV in December peaks around 2. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Sanmu peaks around August 12 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 2 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 4 | 4 | 7 | 8 | 9 | 10 | 10 | 8 | 6 | 3 | 2 |
| Level | Moderate | Moderate | Moderate | High | Very high | Very high | Very high | Extreme | Very high | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Moderate |
| Feb | 4 | Moderate |
| Mar | 4 | Moderate |
| Apr | 7 | High |
| May | 8 | Very high |
| Jun | 9 | Very high |
| Jul | 10 | Very high |
| Aug | 10 | Extreme |
| Sep | 8 | Very high |
| Oct | 6 | High |
| Nov | 3 | Moderate |
| Dec | 2 | Moderate |
Air quality in Sanmu in December
Average fine-particle pollution (PM2.5) through the year — so you can see where December falls, not just the annual average.
Air quality in Sanmu is worst in March — around 25 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (December, 14 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 15 | 18 | 25 | 25 | 24 | 19 | 16 | 15 | 15 | 16 | 16 | 14 |
| Level | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 15 | Moderate |
| Feb | 18 | Moderate |
| Mar | 25 | Moderate |
| Apr | 25 | Moderate |
| May | 24 | Moderate |
| Jun | 19 | Moderate |
| Jul | 16 | Moderate |
| Aug | 15 | Moderate |
| Sep | 15 | Moderate |
| Oct | 16 | Moderate |
| Nov | 16 | Moderate |
| Dec | 14 | Moderate |
Where is Sanmu?
Sanmu sits at 35.6°N, 140.4°E, 52 m above sea level, in Japan. The nearest listed city is Narutō, 3.0 km away.
Topography around Sanmu
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Sanmu.
Within 3 km, the terrain around Sanmu has only modest variations in elevation — a maximum elevation change of 68 m around an average of 31 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 107 m; within 80 km, large variations in elevation — a maximum elevation change of 840 m.
The land around Sanmu is covered by trees (57%) and cropland (27%) within 3 km, trees (34%) and cropland (30%) within 16 km, and water (42%) and trees (23%) within 80 km.
Japan travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type A / B
- 100 V · 50 / 60 Hz
- Prices
- ≈ 65% of US
- price level, 2025
- GDP per capita
- $35,951
- 2025
- Happiness
- 6.1 / 10
- World Happiness, 2025
- Safe drinking water
- 99%
- of population, 2024
- Homicide rate
- 0.2
- per 100k, 2023
- Road deaths
- 3.6
- per 100k/yr, 2019
- Income group
- High
- World Bank
- English
- Very low
- EF EPI 446
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Sanmu (35.6276°, 140.4176°, elevation 52 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).