September weather forecastIyo, Japan
September
Weather in September
September, the first month of the autumn in Iyo, is also a moderately hot month, with an average temperature varying between 25.5°C (77.9°F) and 20.1°C (68.2°F).Temperature
The shift from August to September includes a small decrease in the average high-temperature, from a warm 29.2°C (84.6°F) to a still moderately hot 25.5°C (77.9°F). An average low-temperature of 20.1°C (68.2°F) is observed during September nights.Humidity
In September, the average relative humidity is 80%.Rainfall
In Iyo, Japan, during September, the rain falls for 15.6 days and regularly aggregates up to 66mm (2.6") of precipitation. In Iyo, Japan, during the entire year, the rain falls for 162.8 days and collects up to 749mm (29.49") of precipitation.Snowfall
March through November are months without snowfall.Sea temperature
In Iyo, the average seawater temperature in September is 26.3°C (79.3°F).Note: Water temperatures between 25°C (77°F) and 29°C (84.2°F) are ideal for all water activities, offering enjoyment without causing discomfort over extended periods.
Daylight
In September, the average length of the day is 12h and 23min.On the first day of the month, sunrise is at 05:43 and sunset at 18:35. On the last day of September, in Iyo, sunrise is at 06:02 and sunset at 17:55 JST.
Sunshine
The average sunshine in September in Iyo is 9.4h.UV index
The average daily maximum UV index in September in Iyo, Japan, is 5. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for the average person.Note: The UV index of 5 during September leads to these advisories:
Take precautions - Protection against sun damage is advised. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. Enhance your sun protection with tightly woven, yet airy clothing. Take warning! Reflective sand and water surfaces intensify the Sun's UV rays.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Iyo, Japan
- Average high temperature in September: 25.5°C
The warmest month (with the highest average high temperature) is August (29.2°C).
The month with the lowest average high temperature is January (8°C).
- Average low temperature in September: 20.1°C
The month with the highest average low temperature is August (23.4°C).
The coldest month (with the lowest average low temperature) is January (2.9°C).
Average pressure in September
Iyo, Japan
- Average pressure in September: 1012.4mbar
The month with the highest atmospheric pressure is January (1021mbar).
The month with the lowest atmospheric pressure is June (1008.4mbar).
Average wind speed in September
Iyo, Japan
- Average wind speed in September: 8.1km/h
The windiest month (with the highest average wind speed) is January (12.2km/h).
The calmest month (with the lowest average wind speed) is June (6.6km/h).
Average humidity in September
Iyo, Japan
- Average humidity in September: 80%
The month with the highest relative humidity is July (84%).
The months with the lowest relative humidity are January, February and March (72%).
Average rainfall in September
Iyo, Japan
- Average rainfall in September: 66mm
The wettest month (with the highest rainfall) is June (149mm).
The driest month (with the least rainfall) is January (24mm).
Average rainfall days in September
Iyo, Japan
- Average rainfall days in September: 15.6 days
The month with the highest number of rainy days is July (21.3 days).
The month with the least rainy days is January (8.3 days).
Average snowfall in September
Iyo, Japan
- Average snowfall in September: 0mm
The month with the highest snowfall is December (6mm).
The months with the least snowfall are March, April, May, June, July, August, September, October and November (0mm).
Average snowfall days in September
Iyo, Japan
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (1.3 days).
The months with the least snowfall days are April, May, June, July, August, September, October and November (0 days).
Average sea temperature in September
Iyo, Japan
- Average sea temperature in September: 26.3°C
The best month for swimming (with the highest average sea temperature) is August (27.2°C).
The coldest month (with the lowest average sea temperature) is February (14.7°C).
Average daylight in September /
Average sunshine in September
Iyo, Japan
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in September: 9h and 24min
The month with the most sunshine is August (Average sunshine: 10h and 48min).
The month with the least sunshine is January (Average sunshine: 5h and 12min).
Average sunshine days in September
Iyo, Japan
- Average sunshine days in September: 11.6 days
The month with the most sunshine days is January (20.3 days).
The month with the least sunshine days is August (6.4 days).
Average UV index in September
Iyo, Japan
- Average UV index in September: 5
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January and December (UV index 2).
Average cloud cover in September
Iyo, Japan
- Average cloud cover in September: 35
The month with the most cloud cover is January (Cloud cover 43).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in September
Iyo, Japan
- Average visibility in September: 10km
The months with the highest visibility are January, February, March, August, September, October, November and December (10km).
The months with the lowest visibility are April, May, June and July (9km).
