Japan (関西地方) · Public domain
The descent
The entrance, at 334 m.
The real relief above Akkadō, measured on the Copernicus model every 30 m, and the cave going down at the same vertical scale.
The depth is the one published by those who explored it; the shape of the galleries is a sketch, not a survey. No depth has been published for this cave yet.
334m
Entrance altitude
from the 30 m relief model
9°C
Inside, all year
the yearly average outside, at the entrance
386m
Rock above
the highest point within 1.5 km
Inside and outside
9 °C inside, all year.
Deep inside, a cave keeps the average temperature of the year outside: about 9 °C here, in January and in August. In August the afternoon reaches 24 °C at the entrance, 15 °C warmer than inside: take a jacket. The wettest months are from July to October: water rises fast underground, so never go in without a guide after heavy rain.
- 0°-3°Jan
- 1°-4°Feb
- 4°-1°Mar
- 10°3°Apr
- 15°8°May
- 19°13°Jun
- 22°17°Jul
- 24°19°Aug
- 21°16°Sep
- 16°10°Oct
- 10°4°Nov
- 4°-1°Dec
Outside: afternoon and night averages for 1991–2020 (NASA POWER) brought to the altitude of the entrance. Inside: the yearly average, which deep parts of a cave keep. Near the entrance it follows the weather a little.
Longest cave in Japan, a limestone cave in Iwaizumi Town, Shimohei District, Iwate Prefecture, Japan
Akkadō is a show cave in Japan. The entrance is at 334 m. It has an underground river and stalactites and stalagmites. It is open to visitors.
Getting there.
- Show cave: open to visitorsUsually with a guided tour; check times and tickets on the official site.
- Fudainearest town · 13 km in a straight line
- Iwate Hanamaki Airport (HNA)nearest airport with scheduled flights · 80 km in a straight lineCar hire at AOJ airport (Aomori)Discover Cars · sponsored link↗
Plan the visit
Guided tours, a bed nearby, a car.
Some links above are affiliate links: if you book through them we may earn a commission, at no extra cost to you. It never changes what the data on this page says.
The water
The the river runs highest in April and from July to November.
The the river carries about 3.5 m³/s on average here. It runs highest in April and from July to November.
- 1.9 m³/sJan
- 0.9 m³/sFeb
- 2.9 m³/sMar
- 5.0 m³/sApr
- 4.2 m³/sMay
- 2.5 m³/sJun
- 4.7 m³/sJul
- 5.2 m³/sAug
- 6.7 m³/sSep
- 7.5 m³/sOct
- 4.5 m³/sNov
- 3.1 m³/sDec
From about 0.86 m³/s in the lowest month to 7.5 m³/s in the highest. Its basin above this point covers 144 km².
Estimate: long-term flow from the HydroATLAS model (WaterGAP, 1971–2000) shaped by the monthly rain, snow and temperature of the area (NASA POWER). Dams change it. Not a forecast.
From above.
The ground above the cave, with the relief shaded, the line of the section and what people have mapped around the entrance.
N
1.5 km
Sentinel-2 cloudless 2016 (EOX, CC BY 4.0), 6.0 × 6.0 km, north up. The line is the section above. Points © OpenStreetMap contributors.
Around the entrance.
- 1other cave entrances within 3 km安家洞
- springs within 2 km
- sinkholes within 3 km
- caving clubs and spots within 15 km
- viewpoints within 3 km
- marked hiking routes within 3 km
- climbing crags within 3 km
- named waterfalls within 4 km
- car parks within 2 km
- information boards and visitor centres within 3 km
- bus stops within 2 km
- campsites within 8 km
- hotels and guesthouses within 8 km
- restaurants and cafés within 3 km
Counted in OpenStreetMap, the map anyone can edit, around the entrance. A low number may just mean nobody has mapped it yet. © OpenStreetMap contributors (ODbL).
Towns nearby
- Fudai13 km in a straight line
- Noda15 km in a straight line
- Iwaizumi16 km in a straight line
- Tanohata18 km in a straight line
- Kuji23 km in a straight line
In our other atlases
What else is around Akkadō.
The river at the entrance, the waterfalls, the lakes, the mountains and volcanoes above, the canyons, beaches and islands nearby — from our other atlases.
Peakyas8 mountains within 10 kmFigures from the sister sites' databases (Wikidata, HydroATLAS, GeoNames, NOAA, OpenStreetMap). Links open when each site is online.
Month by month
The weather outside, at the entrance.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Afternoon | 0 | 1 | 4 | 10 | 15 | 19 | 22 | 24 | 21 | 16 | 10 | 4 |
| Afternoon | 0 | 1 | 4 | 10 | 15 | 19 | 22 | 24 | 21 | 16 | 10 | 4 |
| Night | -3 | -4 | -1 | 3 | 8 | 13 | 17 | 19 | 16 | 10 | 4 | -1 |
| Rain (mm) | 78 | 55 | 81 | 88 | 90 | 97 | 148 | 138 | 146 | 135 | 83 | 101 |
| Rainy days | 13 | 11 | 11 | 10 | 11 | 12 | 16 | 15 | 14 | 12 | 12 | 12 |
| Sun hours/day | 2.7 | 3.5 | 4.8 | 5.7 | 5.8 | 5.1 | 3.8 | 4.3 | 4.7 | 4.4 | 3.4 | 2.5 |
| Snow on the ground (cm) | 17 | 17 | 13 | 4 | 0 | 0 | 0 | 0 | 0 | 0 | 4 | 13 |
| Afternoon | Afternoon | Night | Rain (mm) | Sun hours/day | |
|---|---|---|---|---|---|
| Jan | 0 | 0 | -3 | 78 | 2.7 |
| Feb | 1 | 1 | -4 | 55 | 3.5 |
| Mar | 4 | 4 | -1 | 81 | 4.8 |
| Apr | 10 | 10 | 3 | 88 | 5.7 |
| May | 15 | 15 | 8 | 90 | 5.8 |
| Jun | 19 | 19 | 13 | 97 | 5.1 |
| Jul | 22 | 22 | 17 | 148 | 3.8 |
| Aug | 24 | 24 | 19 | 138 | 4.3 |
| Sep | 21 | 21 | 16 | 146 | 4.7 |
| Oct | 16 | 16 | 10 | 135 | 4.4 |
| Nov | 10 | 10 | 4 | 83 | 3.4 |
| Dec | 4 | 4 | -1 | 101 | 2.5 |
Averages 1991–2020 (NASA POWER) for a cell about 55 km wide, brought to the altitude of the entrance (334 m) with the standard lapse rate. Not a forecast.
Photographs
Inside and around.
Recent years
Wet years, dry years.
Rain of each month as a share of the 1991–2020 average. A dry year means a lower river and hotter rock; a wet one, more water in the gorge.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2020 | 162% | 140% | 105% | 183% | 118% | 92% | 258% | 107% | 199% | 72% | 79% | 77% |
| 2021 | 92% | 156% | 163% | 131% | 141% | 71% | 91% | 163% | 68% | 101% | 163% | 93% |
| 2022 | 97% | 60% | 161% | 68% | 76% | 174% | 117% | 292% | 77% | 80% | 108% | 93% |
| 2023 | 80% | 116% | 101% | 115% | 178% | 192% | 113% | 107% | 158% | 75% | 155% | 88% |
| 2024 | 167% | 217% | 102% | 95% | 98% | 96% | 200% | 209% | 207% | 100% | 86% | 83% |
| 2025 | 94% | 89% | 111% | 199% | 202% | 85% | 33% | 129% | 212% | 111% | 207% | 146% |
130% or more: wet month 70% or less: dry month
Caves nearby.
Akkadō
Japan
- —Depth
- —Galleries
- 334 mEntrance altitude
- 9 °CInside, all year
Takkoku-no-Iwaya
Japan · 127 km
- —Depth
- —Galleries
- 80 mEntrance altitude
- 11 °CInside, all year
Where these figures come from
| Name, type, published depth and length, visitors | Wikidata (Q11450564) · CC0 |
|---|---|
| The relief above, the entrance altitude, the section and the 3D model | Copernicus DEM GLO-30 · © DLR e.V., © Airbus Defence and Space GmbH, Copernicus/ESA |
| River flow and basin | HydroATLAS / RiverATLAS v1.0 (Linke et al. 2019) · CC BY 4.0 |
| Climate | NASA POWER, 1991–2020 |
| Entrances, springs, sinkholes, opening hours and what is around | © OpenStreetMap contributors · ODbL |
| Images | EOX Sentinel-2 cloudless 2016 · CC BY 4.0; Wikimedia Commons |
| Rivers, waterfalls, lakes, mountains, canyons, beaches and islands nearby | Coastya, Lakeyas, Peakyas, Cascadyas, Islandyas, Riveryas |
Every figure is an average, an estimate or a count from a public dataset. Licences and methods: data sources.
The family
Do you prefer beaches, lakes, mountains, waterfalls, islands, rivers, canyons, caves, dark skies, viewpoints, birdwatching or forests?
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