Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average sea temperature in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
September
Weather in September
Temperature
During the shift to September, Kosai records a mild decrease in average high-temperature, moving from 29.1°C (84.4°F) in August to a still moderately hot 25.8°C (78.4°F). September introduces a small decrease to a nighttime average of 21.3°C (70.3°F).Humidity
In Kosai, the average relative humidity in September is 77%.Rainfall
In September, the rain falls for 17.1 days. Throughout September, 99mm (3.9") of precipitation is accumulated. In Kosai, Japan, during the entire year, the rain falls for 163.7 days and collects up to 1017mm (40.04") of precipitation.Snowfall
In Kosai, snow does not fall in March through November.Sea temperature
In September, the average sea temperature is 25.8°C (78.4°F).Note: For swimming, diving, or other water activities, temperatures from 25°C (77°F) to 29°C (84.2°F) provide the most enjoyable experience for extended periods without discomfort.
Daylight
In September, the average length of the day is 12h and 24min.On the first day of September, sunrise is at 05:22 and sunset at 18:16. On the last day of the month, sunrise is at 05:43 and sunset at 17:35 JST.
Sunshine
The average sunshine in September is 8.8h.UV index
In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for the average person.Note: In September, a daily maximum UV index of 5 leads to the following instructions:
Act with care - The need to guard against sun damage is communicated. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A hat with a broad brim is indispensable, filtering out up to half of UV rays. Attention! UV strength is notably upped by the reflection of sand and water.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
What is the water temperature in September?
How many hours of daylight does Kosai have in September?
What time are sunrise and sunset in September?
How many hours of sunshine does Kosai have in September?
How high is the UV index in September?
Average temperature in September
Kosai, Japan
- Average high temperature in September: 25.8°C
The warmest month (with the highest average high temperature) is August (29.1°C).
The month with the lowest average high temperature is January (8.4°C).
- Average low temperature in September: 21.3°C
The month with the highest average low temperature is August (24.8°C).
The coldest month (with the lowest average low temperature) is January (3.5°C).
Average pressure in September
Kosai, Japan
- Average pressure in September: 1013mbar
The month with the highest atmospheric pressure is November (1018.7mbar).
The month with the lowest atmospheric pressure is June (1009.1mbar).
Average wind speed in September
Kosai, Japan
- Average wind speed in September: 14.7km/h
The windiest month (with the highest average wind speed) is January (24.2km/h).
The calmest months (with the lowest average wind speed) are July and August (12.8km/h).
Average humidity in September
Kosai, Japan
- Average humidity in September: 77%
The month with the highest relative humidity is July (83%).
The months with the lowest relative humidity are January and February (67%).
Average rainfall in September
Kosai, Japan
- Average rainfall in September: 99mm
The wettest month (with the highest rainfall) is July (190mm).
The driest month (with the least rainfall) is January (27mm).
Average rainfall days in September
Kosai, Japan
- Average rainfall days in September: 17.1 days
The month with the highest number of rainy days is July (20.6 days).
The month with the least rainy days is January (7.5 days).
Average snowfall in September
Kosai, Japan
- Average snowfall in September: 0mm
The month with the highest snowfall is February (2mm).
The months with the least snowfall are March, April, May, June, July, August, September, October and November (0mm).
Average snowfall days in September
Kosai, Japan
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (0.9 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
Kosai, Japan
- Average sea temperature in September: 25.8°C
The best month for swimming (with the highest average sea temperature) is August (26.8°C).
The coldest month (with the lowest average sea temperature) is March (15.1°C).
Average daylight in September /
Average sunshine in September
Kosai, Japan
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in September: 8h and 5min
The month with the most sunshine is August (Average sunshine: 10h and 48min).
The month with the least sunshine is February (Average sunshine: 5h and 54min).
Average sunshine days in September
Kosai, Japan
- Average sunshine days in September: 11 days
The month with the most sunshine days is January (19.9 days).
The month with the least sunshine days is July (8.7 days).
Average UV index in September
Kosai, Japan
- Average UV index in September: 5
The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is January (UV index 2).
Average cloud cover in September
Kosai, Japan
- Average cloud cover in September: 36
The month with the most cloud cover is June (Cloud cover 43).
The month with the least cloud cover is January (Cloud cover 28).
Average visibility in September
Kosai, Japan
- Average visibility in September: 10km
The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (10km).
The month with the lowest visibility is July (9km).
