Tonosho, located on Shodoshima Island in Kagawa Prefecture, enjoys a humid subtropical climate with four distinct seasons. Summers are hot, humid, and occasionally rainy, while winters are mild and mostly clear. The town benefits from its coastal setting, which moderates temperature extremes and provides abundant sunshine throughout the year.
Tonosho’s climate is shaped by its coastal location and the influence of the warm Kuroshio Current. The town experiences hot, humid summers with average temperatures ranging from 25°C to 30°C between June and August. Rainfall is most frequent in June and September, coinciding with the rainy and typhoon seasons, but showers can occur throughout the year. Humidity is high in summer, making conditions feel warmer and more oppressive. Winds are generally from the southwest in summer, bringing moist ocean air.
Winters in Tonosho are relatively mild, with average temperatures between 5°C and 12°C from December to February. Snow is rare, and most winter days are clear, though occasional rain and brisk northwest winds can make it feel cooler. Spring and autumn are particularly pleasant, with temperatures ranging from 10°C to 25°C and lower humidity. These seasons are ideal for outdoor activities, as the town’s parks and natural scenery are at their most vibrant. Tonosho receives around 1,400 mm of rainfall annually, and enjoys 2,000–2,500 hours of sunshine per year, with the sunniest months in July and August.
| Average climate data for Tonosho, Japan | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Average maximum temperature (°C) | -6 | -4 | 1 | 10 | 18 | 22 | 26 | 25 | 21 | 13 | 5 | -2 | 26 |
| Average minimum temperature (°C) | -13 | -12 | -6 | 1 | 9 | 13 | 16 | 15 | 11 | 6 | -1 | -8 | -13 |
| Average precipitation (mm) | 67 | 63 | 69 | 79 | 86 | 78 | 68 | 79 | 56 | 83 | 70 | 74 | 874 |
| Average rainfall days (days) | 6 | 6 | 11 | 17 | 18 | 18 | 18 | 17 | 12 | 16 | 11 | 8 | 160 |
| Average snowfall (mm) | 292 | 266 | 164 | 58 | 1 | 0 | 0 | 0 | 0 | 3 | 127 | 214 | 1,125 |
| Average snowfall days (days) | 19 | 18 | 13 | 5 | 0 | 0 | 0 | 0 | 0 | 1 | 6 | 15 | 78 |
| Average relative humidity (%) | 91 | 91 | 85 | 73 | 73 | 77 | 77 | 78 | 76 | 78 | 78 | 86 | 80 |
| Average wind speed (km/h) | 14 | 14 | 14 | 14 | 13 | 12 | 11 | 11 | 11 | 13 | 14 | 13 | 13 |
| Average water temperature (°C) | 16 | 15 | 15 | 17 | 19 | 23 | 26 | 28 | 26 | 24 | 22 | 19 | 21 |
| Average daily daylight hours (h) | 9 | 10 | 12 | 13 | 14 | 15 | 15 | 14 | 12 | 10 | 9 | 8 | 12 |
| Average daily sunshine hours (h) | 3 | 2 | 4 | 6 | 8 | 8 | 10 | 10 | 8 | 5 | 4 | 3 | 6 |
| Average cloud coverage (%) | 69 | 70 | 64 | 58 | 46 | 42 | 34 | 37 | 38 | 49 | 54 | 66 | 52 |
| Average UV index | 1 | 1 | 2 | 3 | 4 | 5 | 6 | 5 | 3 | 2 | 2 | 1 | 3 |
The best times to visit Tonosho are in spring (April to May) and autumn (October to November). These months offer mild temperatures, low humidity, and abundant sunshine, making them ideal for sightseeing, enjoying cherry blossoms or autumn foliage, and outdoor activities. Rainfall is moderate and weather conditions are generally stable.
The least favourable time to visit Tonosho is during the rainy season in June and the typhoon-prone period in September, when humidity and rainfall are at their highest. Summer (July–August) can also be hot and muggy, with occasional heavy showers and high UV levels.
Tonosho’s average annual temperature ranges from 5°C in winter to 30°C in summer. The hottest months are July and August, while January is the coldest, with average highs around 8°C and lows of 5°C.
Tonosho receives about 1,400 mm of rainfall annually. The wettest months are June and September, coinciding with the rainy and typhoon seasons. Showers can occur year-round, but winters are generally drier.
Snow is rare in Tonosho. Winters are mild and mostly dry, with temperatures rarely dropping below freezing. Occasional rain and brisk winds can make it feel chilly, but snow is uncommon.
Cherry blossoms typically bloom from late March to early April in Tonosho. This is a popular time for visitors, with parks and scenic spots hosting hanami (blossom viewing) events.
Typhoons can occasionally impact Tonosho, especially from late summer to early autumn. While direct hits are rare, travellers should monitor weather forecasts for possible disruptions during this period.
Pack light layers for spring and autumn, breathable clothing and rain gear for summer, and a warm jacket for winter. Sun protection is essential in summer due to high UV levels.
Tonosho enjoys 2,000–2,500 hours of sunshine annually. The sunniest months are July and August, while winter months have fewer sunshine hours but are generally clear.
The warmest month, with the highest average maximum temperature, is July (25.7 °C). The month with the lowest average maximum temperature is January (-5.8 °C). Overall, the average maximum temperature over the whole year is 10.7 °C.
The month with the highest average minimum temperature is July (15.8 °C). The coldest month, with the lowest average minimum temperature, is January (-13.1 °C). Overall, the average minimum temperature over the whole year is 2.7 °C.
The month with the highest average water temperature is August (27.6 °C). The month with the lowest average water temperature is February (15.3 °C). Overall, the average water temperature over the whole year is 20.9 °C.
The wettest month, with the highest amount of precipitation, is May (86.1 mm). The driest month, with the least amount of precipitation, is September (55.8 mm). Over the whole year there are 874.1 mm of rainfall on average.
The month with the most days of rain is July (18.4 days). The month with the fewest days of rain is January (5.7 days). Over the whole year there are 159.7 days of rain on average.
The month with the most snowfall is January (291.5 mm). The months with the least snowfall are June, July, August and September (0 mm). Over the whole year there are 1,124.5 mm of snowfall on average.
The month with the most days of snowfall is January (18.9 days). The months with the fewest days of snowfall are June, July and September (0 days). Over the whole year there are 77.6 days of snowfall on average.
The month with the highest average relative humidity is January (90.9 %). The month with the lowest average relative humidity is April (72.9 %). The overall average relative humidity over the whole year is 80.2 %.
The windiest month, with the highest average wind speed, is April (14.2 km/h). The calmest month, with the lowest average wind speed, is August (10.7 km/h). The overall average wind speed over the whole year is 12.7 km/h.
The month with the cloudiest skies, so the highest cloud coverage, is February (70.2 %). The month with the clearest skies, so the lowest cloud coverage, is July (33.6 %). Over the whole year there is an average cloud coverage of 52.2 %.
The month with the longest days, so the most daylight, is June (Average daylight: 15.1 h). The month with the shortest days, so the least daylight, is December (Average daylight: 8.1 h). Over the whole year there are 11.8 h of daylight per day on average.
The month with the most sunshine per day is July (Average sunshine: 10 h). The month with the least sunshine per day is February (Average sunshine: 2 h). Over the whole year there are 5.9 h of sunlight per day on average.
The month with the highest average UV index is July (UV index: 6). The months with the lowest average UV index are January, February and December (UV index: 1). Over the whole year the average UV index is 2.9.
