Innoshima, Japan Climate
The warmest month is August, with an average high of 30°C; the coldest is January, with an average low of 0°C. A normal year brings 1478 mm of precipitation.
Temperature through the year
The normal daily high and low. The line marks today.
- Normal low
- Normal high
- Reanalysis extreme high
- Reanalysis extreme low
Normals for Sep 25
- Normal high
- 25°C
- Normal low
- 17°C
- Reanalysis high
- 29°Cin 2009
- Reanalysis low
- 13°Cin 1993
- Chance of a wet day
- 40%
- Daylight
- 12 h 04 min
Month by month
Averages for 1991-2020. Wet days have at least 1 mm of precipitation in the reanalysis. Each month links to its own page.
| Month | Avg high | Avg low | Warmest | Coldest | Precipitation | Wet days |
|---|---|---|---|---|---|---|
| January | 7°C | 0°C | 18°C (2002) | -6°C (2016) | 62 mm | 9.3 |
| February | 9°C | 1°C | 19°C (2004) | -6°C (1991) | 68 mm | 11.3 |
| March | 12°C | 3°C | 21°C (2010) | -3°C (2016) | 105 mm | 12.4 |
| April | 18°C | 7°C | 26°C (2005) | -1°C (1991) | 117 mm | 12.0 |
| May | 22°C | 12°C | 31°C (2014) | 4°C (2013) | 140 mm | 12.4 |
| June | 26°C | 17°C | 33°C (2005) | 10°C (2017) | 207 mm | 15.0 |
| July | 29°C | 22°C | 37°C (1994) | 15°C (2008) | 229 mm | 15.5 |
| August | 30°C | 23°C | 38°C (1994) | 16°C (2009) | 121 mm | 12.4 |
| September | 27°C | 19°C | 37°C (1994) | 10°C (1992) | 174 mm | 12.0 |
| October | 21°C | 13°C | 29°C (2013) | 5°C (2002) | 112 mm | 9.3 |
| November | 16°C | 7°C | 24°C (1996) | 0°C (2008) | 75 mm | 9.0 |
| December | 10°C | 2°C | 22°C (2018) | -4°C (2005) | 68 mm | 9.3 |
| Year | 19°C | 11°C | 1478 mm | 140 |
Precipitation
Rain and melted snow together. The chance of a wet day is the share of days with at least 1 mm of precipitation in the reanalysis.
1478 mm in a normal year, most in July.
Chance of a wet day
- Chance of a wet day
Humidity and comfort
NASA POWER reanalysis, 1991-2020, for the grid cell around Innoshima.
The muggiest month is July, when 97 percent of days are muggy or worse, with a mean dew point of 18°C or more.
| Month | Dew point | Humidity | Dry | Comfortable | Humid | Muggy | Oppressive | Miserable |
|---|---|---|---|---|---|---|---|---|
| January | 0°C | 81% | 100% | 0% | 0% | 0% | 0% | 0% |
| February | 1°C | 79% | 100% | 0% | 0% | 0% | 0% | 0% |
| March | 3°C | 78% | 99% | 1% | 0% | 0% | 0% | 0% |
| April | 8°C | 77% | 87% | 10% | 2% | 0% | 0% | 0% |
| May | 13°C | 78% | 46% | 34% | 16% | 4% | 0% | 0% |
| June | 18°C | 82% | 5% | 17% | 37% | 27% | 14% | 0% |
| July | 22°C | 85% | 0% | 0% | 3% | 19% | 68% | 10% |
| August | 23°C | 81% | 0% | 0% | 2% | 15% | 63% | 19% |
| September | 19°C | 81% | 5% | 12% | 26% | 30% | 26% | 2% |
| October | 13°C | 80% | 48% | 28% | 17% | 6% | 1% | 0% |
| November | 8°C | 80% | 89% | 8% | 3% | 0% | 0% | 0% |
| December | 3°C | 81% | 99% | 0% | 0% | 0% | 0% | 0% |
Comfort is judged by the day's mean dew point: dry below 13°C, comfortable to 16°C, humid to 18°C, muggy to 21°C, oppressive to 24°C, miserable above.
Clouds
Average share of the sky covered, from satellite (CERES and GEWEX SRB) by way of NASA POWER, 1991-2020.
The clearest month is April, with the sky 66 percent covered on average; the cloudiest is June, at 79 percent.
Wind
The mean wind speed over the whole day, from the MERRA-2 reanalysis by way of NASA POWER. Gusts run well above it.
The windiest month is January, averaging 16.6 km/h at 10 meters (33 feet) above the ground.
Daylight and sunshine
The longest day is Jun 17, with 14 h 27 min of daylight; the shortest is Dec 16, with 9 h 52 min.
- Day length
Solar energy
Average daily sunshine reaching the ground on a flat surface, in kilowatt-hours per square meter, clouds included.
Month pages
The weather in Innoshima in each month, day by day.
What this means
A normal is the average of the thirty years 1991 to 2020, the period the World Meteorological Organization and NOAA use for comparison. It is an average, not a forecast: most days depart from it, and some by a long way.
Where no station record is within reach, the extremes shown are the highest and lowest the reanalysis produced for the date in 1991-2020, not measured records.
Cloud, humidity, wind and sunshine come from a reanalysis: a weather model run over the past with every observation fed in, averaged over a grid cell about 50 km across. It is consistent everywhere on Earth; it smooths local detail such as a lake shore or a valley.
More for this place
Nearby
Sources
Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.