Yotsukaidō weather in April
In April, Yotsukaidō sees average daytime highs of 18°C and overnight lows near 10°C, with 113 mm of rain across 12.6 wet days and about 12.9 hours of daylight. It is the 7th-warmest and 8th-wettest month of the year here.
Highs climb over the month, from about 16°C in the first days to 20°C by the end. The sky is clear or mostly clear about 30% of the time in April, and the air most often feels dry.
Daylight stretches from about 12 h 18 min at the start of April to 13 h 24 min by month's end. Set against the rest of the year, April is Yotsukaidō's 7th-clearest and 1st-windiest month. For the whole year in context, see Yotsukaidō's year-round climate.
- Daytime high
- 18°
- 7th warmest
- Overnight low
- 10°
- 6th coldest
- Rainfall
- 113 mm
- 12.6 wet days
- Daylight
- 12 h 54 min
- 5:13 AM – 6:07 PM
- Cloud cover
- 62%
- 7th clearest
- Wind
- 13 km/h
- 1st windiest
- Solar energy
- 4.94 kWh/m²
- Travel score
- 5.3
- out of 10
Yotsukaidō is city in Chiba Prefecture, Japan.
- Density
- 2,760/km²
- people per km²
- Founded
- 1981
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Temperature in April
Highs climb over the month, from about 16°C in the first days to 20°C by the end.
A typical April day in Yotsukaidō reaches about 18°C in the afternoon and slips back to 10°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 13°C and 22°C. Set against its neighbours, April runs about 5°C warmer than March and about 4°C cooler than May.
| 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 15 | 16 | 16 | 16 | 16 | 16 | 16 | 17 | 17 | 17 | 17 | 17 | 17 | 18 | 18 | 18 | 18 | 18 | 18 | 19 | 19 | 19 | 19 | 19 | 19 | 20 | 20 | 20 | 20 | 20 |
| Avg low (°C) | 8 | 8 | 8 | 8 | 9 | 9 | 9 | 9 | 9 | 9 | 10 | 10 | 10 | 10 | 10 | 11 | 11 | 11 | 11 | 11 | 11 | 12 | 12 | 12 | 12 | 12 | 12 | 13 | 13 | 13 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| 1 | 15 | 8 |
| 2 | 16 | 8 |
| 3 | 16 | 8 |
| 4 | 16 | 8 |
| 5 | 16 | 9 |
| 6 | 16 | 9 |
| 7 | 16 | 9 |
| 8 | 17 | 9 |
| 9 | 17 | 9 |
| 10 | 17 | 9 |
| 11 | 17 | 10 |
| 12 | 17 | 10 |
| 13 | 17 | 10 |
| 14 | 18 | 10 |
| 15 | 18 | 10 |
| 16 | 18 | 11 |
| 17 | 18 | 11 |
| 18 | 18 | 11 |
| 19 | 18 | 11 |
| 20 | 19 | 11 |
| 21 | 19 | 11 |
| 22 | 19 | 12 |
| 23 | 19 | 12 |
| 24 | 19 | 12 |
| 25 | 19 | 12 |
| 26 | 20 | 12 |
| 27 | 20 | 12 |
| 28 | 20 | 13 |
| 29 | 20 | 13 |
| 30 | 20 | 13 |
How April really feels in Yotsukaidō
Once humidity and wind are folded in, April 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.
April sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
Yotsukaidō weather by month
How April compares with the rest of the year at a glance. April is the 7th-warmest and 8th-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° / 2° | 75 | 7.6 | 0.8 | 9.9 | 2.1 |
| Feb | 10° / 3° | 71 | 8.4 | 1.1 | 10.7 | 2.3 |
| Mar | 13° / 6° | 125 | 12.8 | 0.5 | 11.7 | 3.5 |
| Apr | 18° / 10° | 113 | 12.6 | 0 | 12.9 | 5.3 |
| May | 22° / 15° | 128 | 11.6 | 0 | 13.9 | 6.3 |
| Jun | 25° / 19° | 159 | 13.7 | 0 | 14.4 | 5.8 |
| Jul | 29° / 23° | 150 | 13.8 | 0 | 14.2 | 4.9 |
| Aug | 30° / 24° | 114 | 11.9 | 0 | 13.3 | 4.5 |
| Sep | 27° / 21° | 175 | 14.3 | 0 | 12.2 | 5.6 |
| Oct | 21° / 16° | 207 | 13 | 0 | 11.1 | 6.1 |
| Nov | 16° / 10° | 102 | 10.4 | 0 | 10.1 | 5.2 |
| Dec | 12° / 5° | 68 | 8.4 | 0.1 | 9.6 | 3.2 |
Cloud cover in April
The sky is clear or mostly clear about 30% of the time in April.
Beyond those clear spells, partly cloudy skies cover about 14% of April, with mostly cloudy or overcast conditions the remaining 56%.
| 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 46 | 46 | 46 | 46 | 45 | 45 | 45 | 45 | 45 | 44 | 44 | 43 | 43 | 43 | 43 | 43 | 43 | 41 | 42 | 42 | 42 | 43 | 43 | 43 | 43 | 43 | 43 | 43 | 43 | 43 |
| Cloudier (%) | 54 | 54 | 54 | 54 | 55 | 55 | 55 | 55 | 55 | 56 | 56 | 57 | 57 | 57 | 57 | 57 | 57 | 59 | 58 | 58 | 58 | 57 | 57 | 57 | 57 | 57 | 57 | 57 | 57 | 57 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| 1 | 46 | 54 |
| 2 | 46 | 54 |
| 3 | 46 | 54 |
| 4 | 46 | 54 |
| 5 | 45 | 55 |
| 6 | 45 | 55 |
| 7 | 45 | 55 |
| 8 | 45 | 55 |
| 9 | 45 | 55 |
| 10 | 44 | 56 |
| 11 | 44 | 56 |
| 12 | 43 | 57 |
| 13 | 43 | 57 |
| 14 | 43 | 57 |
| 15 | 43 | 57 |
| 16 | 43 | 57 |
| 17 | 43 | 57 |
| 18 | 41 | 59 |
| 19 | 42 | 58 |
| 20 | 42 | 58 |
| 21 | 42 | 58 |
| 22 | 43 | 57 |
| 23 | 43 | 57 |
| 24 | 43 | 57 |
| 25 | 43 | 57 |
| 26 | 43 | 57 |
| 27 | 43 | 57 |
| 28 | 43 | 57 |
| 29 | 43 | 57 |
| 30 | 43 | 57 |
Chance of precipitation in April
Yotsukaidō gets around 113 mm of rain over 12.6 wet days in April. The line is the day-by-day chance of measurable precipitation.
Day to day, the chance of measurable rain averages around 42% and peaks near 43% on the wettest days.
| 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain chance (%) | 43 | 43 | 43 | 43 | 43 | 43 | 43 | 43 | 43 | 43 | 43 | 42 | 42 | 42 | 42 | 42 | 42 | 42 | 41 | 41 | 41 | 41 | 41 | 40 | 40 | 40 | 39 | 39 | 38 | 38 |
| Rain chance (%) | |
|---|---|
| 1 | 43 |
| 2 | 43 |
| 3 | 43 |
| 4 | 43 |
| 5 | 43 |
| 6 | 43 |
| 7 | 43 |
| 8 | 43 |
| 9 | 43 |
| 10 | 43 |
| 11 | 43 |
| 12 | 42 |
| 13 | 42 |
| 14 | 42 |
| 15 | 42 |
| 16 | 42 |
| 17 | 42 |
| 18 | 42 |
| 19 | 41 |
| 20 | 41 |
| 21 | 41 |
| 22 | 41 |
| 23 | 41 |
| 24 | 40 |
| 25 | 40 |
| 26 | 40 |
| 27 | 39 |
| 28 | 39 |
| 29 | 38 |
| 30 | 38 |
Humidity in April
Most of April feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
By dew point, April lands in the dry band about 86% 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 97 | 96 | 96 | 96 | 95 | 95 | 94 | 93 | 92 | 92 | 91 | 91 | 90 | 90 | 89 | 88 | 87 | 86 | 84 | 83 | 82 | 81 | 79 | 77 | 76 | 73 | 72 | 70 | 69 | 67 |
| Comfortable (%) | 3 | 4 | 4 | 4 | 5 | 5 | 6 | 6 | 7 | 7 | 8 | 8 | 9 | 9 | 10 | 11 | 12 | 12 | 13 | 14 | 15 | 16 | 18 | 19 | 20 | 22 | 23 | 24 | 25 | 26 |
| Humid (%) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2 | 2 | 2 | 2 | 2 | 2 | 3 | 3 | 4 | 4 | 5 | 5 | 6 |
| Muggy (%) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | |
|---|---|---|---|---|
| 1 | 97 | 3 | 0 | 0 |
| 2 | 96 | 4 | 0 | 0 |
| 3 | 96 | 4 | 0 | 0 |
| 4 | 96 | 4 | 0 | 0 |
| 5 | 95 | 5 | 0 | 0 |
| 6 | 95 | 5 | 0 | 0 |
| 7 | 94 | 6 | 0 | 0 |
| 8 | 93 | 6 | 1 | 0 |
| 9 | 92 | 7 | 1 | 0 |
| 10 | 92 | 7 | 1 | 0 |
| 11 | 91 | 8 | 1 | 0 |
| 12 | 91 | 8 | 1 | 0 |
| 13 | 90 | 9 | 1 | 0 |
| 14 | 90 | 9 | 1 | 0 |
| 15 | 89 | 10 | 1 | 0 |
| 16 | 88 | 11 | 1 | 0 |
| 17 | 87 | 12 | 1 | 0 |
| 18 | 86 | 12 | 2 | 0 |
| 19 | 84 | 13 | 2 | 1 |
| 20 | 83 | 14 | 2 | 1 |
| 21 | 82 | 15 | 2 | 1 |
| 22 | 81 | 16 | 2 | 1 |
| 23 | 79 | 18 | 2 | 1 |
| 24 | 77 | 19 | 3 | 1 |
| 25 | 76 | 20 | 3 | 1 |
| 26 | 73 | 22 | 4 | 1 |
| 27 | 72 | 23 | 4 | 1 |
| 28 | 70 | 24 | 5 | 1 |
| 29 | 69 | 25 | 5 | 1 |
| 30 | 67 | 26 | 6 | 1 |
Wind in April
Winds average 13 km/h in April, the windiest month of the year.
Across April, daily wind ranges from about 13 km/h on the calmest days to 13 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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 | 13 | 13 | 13 | 13 | 13 | 13 |
| 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 |
| 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 | 13 | light breeze |
| 26 | 13 | light breeze |
| 27 | 13 | light breeze |
| 28 | 13 | light breeze |
| 29 | 13 | light breeze |
| 30 | 13 | light breeze |
Sunrise & sunset in April
Daylight runs from about 12 h 18 min at the start of April to 13 h 24 min by month's end. The lit band spans sunrise to sunset each day.
Days grow by about 66 minutes over April. Sunrise moves from 5:34 AM to 4:55 AM, and sunset from 5:54 PM to 6:18 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 12.3 | 12.4 | 12.4 | 12.5 | 12.5 | 12.5 | 12.6 | 12.6 | 12.6 | 12.7 | 12.7 | 12.8 | 12.8 | 12.8 | 12.9 | 12.9 | 12.9 | 13.0 | 13.0 | 13.0 | 13.1 | 13.1 | 13.2 | 13.2 | 13.2 | 13.3 | 13.3 | 13.3 | 13.4 | 13.4 |
| Sunrise (AM) | 5:34 | 5:32 | 5:31 | 5:29 | 5:28 | 5:27 | 5:25 | 5:24 | 5:22 | 5:21 | 5:19 | 5:18 | 5:17 | 5:15 | 5:14 | 5:13 | 5:11 | 5:10 | 5:09 | 5:07 | 5:06 | 5:05 | 5:03 | 5:02 | 5:01 | 5:00 | 4:58 | 4:57 | 4:56 | 4:55 |
| Sunset (PM) | 5:54 | 5:55 | 5:56 | 5:57 | 5:57 | 5:58 | 5:59 | 6:00 | 6:01 | 6:02 | 6:02 | 6:03 | 6:04 | 6:05 | 6:06 | 6:07 | 6:07 | 6:08 | 6:09 | 6:10 | 6:11 | 6:12 | 6:12 | 6:13 | 6:14 | 6:15 | 6:16 | 6:17 | 6:18 | 6:18 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| 1 | 12.3 | 5:34 | 5:54 |
| 2 | 12.4 | 5:32 | 5:55 |
| 3 | 12.4 | 5:31 | 5:56 |
| 4 | 12.5 | 5:29 | 5:57 |
| 5 | 12.5 | 5:28 | 5:57 |
| 6 | 12.5 | 5:27 | 5:58 |
| 7 | 12.6 | 5:25 | 5:59 |
| 8 | 12.6 | 5:24 | 6:00 |
| 9 | 12.6 | 5:22 | 6:01 |
| 10 | 12.7 | 5:21 | 6:02 |
| 11 | 12.7 | 5:19 | 6:02 |
| 12 | 12.8 | 5:18 | 6:03 |
| 13 | 12.8 | 5:17 | 6:04 |
| 14 | 12.8 | 5:15 | 6:05 |
| 15 | 12.9 | 5:14 | 6:06 |
| 16 | 12.9 | 5:13 | 6:07 |
| 17 | 12.9 | 5:11 | 6:07 |
| 18 | 13.0 | 5:10 | 6:08 |
| 19 | 13.0 | 5:09 | 6:09 |
| 20 | 13.0 | 5:07 | 6:10 |
| 21 | 13.1 | 5:06 | 6:11 |
| 22 | 13.1 | 5:05 | 6:12 |
| 23 | 13.2 | 5:03 | 6:12 |
| 24 | 13.2 | 5:02 | 6:13 |
| 25 | 13.2 | 5:01 | 6:14 |
| 26 | 13.3 | 5:00 | 6:15 |
| 27 | 13.3 | 4:58 | 6:16 |
| 28 | 13.3 | 4:57 | 6:17 |
| 29 | 13.4 | 4:56 | 6:18 |
| 30 | 13.4 | 4:55 | 6:18 |
Solar energy in April
Average shortwave solar energy reaching the ground each day in April, about 4.94 kWh/m².
For context, solar energy here swings from a low near 2.32 kWh/m² to a high of 5.31 kWh/m² in May across the year — April's 4.94 kWh/m² falls in the middle.
| 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 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 4.6 | 4.6 | 4.6 | 4.7 | 4.7 | 4.7 | 4.7 | 4.7 | 4.8 | 4.8 | 4.8 | 4.8 | 4.8 | 4.8 | 4.9 | 4.9 | 4.9 | 4.9 | 5.0 | 5.0 | 5.0 | 5.0 | 5.1 | 5.1 | 5.1 | 5.2 | 5.2 | 5.2 | 5.3 | 5.3 |
| Level | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| 1 | 4.6 | Bright |
| 2 | 4.6 | Bright |
| 3 | 4.6 | Bright |
| 4 | 4.7 | Bright |
| 5 | 4.7 | Bright |
| 6 | 4.7 | Bright |
| 7 | 4.7 | Bright |
| 8 | 4.7 | Bright |
| 9 | 4.8 | Bright |
| 10 | 4.8 | Bright |
| 11 | 4.8 | Bright |
| 12 | 4.8 | Bright |
| 13 | 4.8 | Bright |
| 14 | 4.8 | Bright |
| 15 | 4.9 | Bright |
| 16 | 4.9 | Bright |
| 17 | 4.9 | Bright |
| 18 | 4.9 | Bright |
| 19 | 5.0 | Bright |
| 20 | 5.0 | Bright |
| 21 | 5.0 | Bright |
| 22 | 5.0 | Bright |
| 23 | 5.1 | Bright |
| 24 | 5.1 | Bright |
| 25 | 5.1 | Bright |
| 26 | 5.2 | Bright |
| 27 | 5.2 | Bright |
| 28 | 5.2 | Bright |
| 29 | 5.3 | Bright |
| 30 | 5.3 | Bright |
Hazard calendar for Yotsukaidō
In April, Yotsukaidō sits inside its pacific typhoon season. The full year is below, with each hazard's peak months called out.
Yotsukaidō sits in the Pacific typhoon belt; the season peaks July–October.
Is April a good time to visit Yotsukaidō?
Our two travel scores rate April for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).
April is a reasonable time to visit Yotsukaidō for sightseeing.
What to pack for Yotsukaidō in April
From April's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In April, Yotsukaidō sees daytime highs around 18°C and nights near 10°C. Worth packing: rain gear and sun protection. About 13 days see rain.
Sea temperature near Yotsukaidō in April
The nearest coast averages about 15°C in April — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 27 km away) is warmest in August at about 26°C and coldest in February near 13°C.
It's comfortable for a long swim from Jun 7 to Nov 3 — about 4.9 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 14 | 13 | 13 | 15 | 18 | 21 | 23 | 26 | 25 | 22 | 19 | 16 |
| Comfort | Bracing | Bracing | Bracing | Cool | Cool | Refreshing | Refreshing | Warm | Warm | Refreshing | Cool | Cool |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 14 | Bracing |
| Feb | 13 | Bracing |
| Mar | 13 | Bracing |
| Apr | 15 | Cool |
| May | 18 | Cool |
| Jun | 21 | Refreshing |
| Jul | 23 | Refreshing |
| Aug | 26 | Warm |
| Sep | 25 | Warm |
| Oct | 22 | Refreshing |
| Nov | 19 | Cool |
| Dec | 16 | Cool |
UV index in Yotsukaidō in April
Clear-sky midday UV in April peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Yotsukaidō peaks around August 10 at about 10 (very high) — 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 | Very high | 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 | Very high |
| Sep | 8 | Very high |
| Oct | 6 | High |
| Nov | 3 | Moderate |
| Dec | 2 | Moderate |
Air quality in Yotsukaidō in April
Average fine-particle pollution (PM2.5) through the year — so you can see where April falls, not just the annual average.
Air quality in Yotsukaidō 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 Yotsukaidō?
Yotsukaidō sits at 35.6°N, 140.2°E, 25 m above sea level, in Japan. The nearest listed city is Chiba, 7.0 km away.
Topography around Yotsukaidō
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Yotsukaidō.
Within 3 km, the terrain around Yotsukaidō has only modest variations in elevation — a maximum elevation change of 48 m around an average of 30 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 111 m; within 80 km, large variations in elevation — a maximum elevation change of 840 m.
The land around Yotsukaidō is covered by artificial surfaces (65%) and trees (28%) within 3 km, artificial surfaces (38%) and trees (34%) within 16 km, and water (36%), artificial surfaces (24%) 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 Yotsukaidō (35.65°, 140.1667°, elevation 25 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).