| Average climate data for Shimabara, Japan | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Average maximum temperature (°C) | 31 | 30 | 29 | 28 | 25 | 23 | 23 | 24 | 26 | 28 | 30 | 31 | 31 |
| Average minimum temperature (°C) | 23 | 23 | 22 | 20 | 17 | 14 | 13 | 15 | 17 | 19 | 22 | 23 | 13 |
| Average precipitation (mm) | 279 | 294 | 319 | 149 | 111 | 70 | 54 | 34 | 18 | 46 | 75 | 171 | 1,621 |
| Average rainfall days (days) | 12 | 13 | 12 | 10 | 9 | 7 | 6 | 6 | 4 | 5 | 6 | 9 | 99 |
| Average snowfall (mm) | 6 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 11 |
| Average snowfall days (days) | 3 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 5 |
| Average relative humidity (%) | 71 | 72 | 69 | 71 | 73 | 83 | 84 | 78 | 75 | 73 | 73 | 71 | 74 |
| Average wind speed (km/h) | 12 | 13 | 12 | 11 | 9 | 9 | 10 | 9 | 10 | 12 | 11 | 13 | 11 |
| Average water temperature (°C) | 28 | 28 | 28 | 27 | 25 | 23 | 22 | 22 | 23 | 25 | 26 | 27 | 25 |
| Average daily daylight hours (h) | 13 | 12 | 12 | 11 | 11 | 10 | 11 | 11 | 12 | 12 | 13 | 13 | 12 |
| Average daily sunshine hours (h) | 9 | 7 | 7 | 7 | 7 | 7 | 7 | 9 | 9 | 10 | 9 | 9 | 8 |
| Average cloud coverage (%) | 44 | 44 | 40 | 38 | 36 | 48 | 43 | 31 | 34 | 29 | 33 | 43 | 39 |
| Average UV index | 12 | 12 | 12 | 10 | 7 | 6 | 6 | 8 | 10 | 12 | 12 | 12 | 10 |
The warmest month, with the highest average maximum temperature, is January (31 °C). The month with the lowest average maximum temperature is June (22.9 °C). Overall, the average maximum temperature over the whole year is 27.3 °C.
The month with the highest average minimum temperature is February (22.9 °C). The coldest month, with the lowest average minimum temperature, is July (13.1 °C). Overall, the average minimum temperature over the whole year is 19 °C.
The month with the highest average water temperature is March (28.1 °C). The month with the lowest average water temperature is August (21.9 °C). Overall, the average water temperature over the whole year is 25.4 °C.
The wettest month, with the highest amount of precipitation, is March (318.7 mm). The driest month, with the least amount of precipitation, is September (18.1 mm). Over the whole year there are 1,621.3 mm of rainfall on average.
The month with the most days of rain is February (13 days). The month with the fewest days of rain is September (4.1 days). Over the whole year there are 98.8 days of rain on average.
The month with the most snowfall is January (5.9 mm). The months with the least snowfall are March, April, May, June, July, August, September, October and November (0 mm). Over the whole year there are 10.9 mm of snowfall on average.
The month with the most days of snowfall is January (2.8 days). The months with the fewest days of snowfall are June, August, September, October and November (0 days). Over the whole year there are 5 days of snowfall on average.
The month with the highest average relative humidity is July (84 %). The month with the lowest average relative humidity is March (69.2 %). The overall average relative humidity over the whole year is 74.5 %.
The windiest month, with the highest average wind speed, is December (12.6 km/h). The calmest month, with the lowest average wind speed, is June (9 km/h). The overall average wind speed over the whole year is 11 km/h.
The month with the cloudiest skies, so the highest cloud coverage, is June (48.5 %). The month with the clearest skies, so the lowest cloud coverage, is October (29 %). Over the whole year there is an average cloud coverage of 38.6 %.
The month with the longest days, so the most daylight, is December (Average daylight: 13 h). The month with the shortest days, so the least daylight, is June (Average daylight: 10.1 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 October (Average sunshine: 10 h). The month with the least sunshine per day is July (Average sunshine: 6.9 h). Over the whole year there are 8.1 h of sunlight per day on average.
The months with the highest average UV index are January, February, March, October, November and December (UV index: 12). The months with the lowest average UV index are June and July (UV index: 6). Over the whole year the average UV index is 9.9.
