September weather forecast
Iwakuni, Japan

September

Weather in September

September, the first month of the autumn in Iwakuni, is still a warm month, with an average temperature fluctuating between 19.7°C (67.5°F) and 25.5°C (77.9°F).

Temperature

The transition to September results in a modest reduction in average high-temperature, moving from 29.2°C (84.6°F) in August to a still warm 25.5°C (77.9°F). Iwakuni's nighttime temperature during September is consistently averaged at an enjoyable 19.7°C (67.5°F).

Humidity

In September, the average relative humidity in Iwakuni is 80%.

Rainfall

In September, the rain falls for 13.9 days. Throughout September, 47mm (1.85") of precipitation is accumulated. In Iwakuni, Japan, during the entire year, the rain falls for 161.2 days and collects up to 650mm (25.59") of precipitation.

Snowfall

In Iwakuni, Japan, snow does not fall in April through November.

Daylight

The average length of the day in September is 12h and 24min.
On the first day of the month, sunrise is at 05:44 and sunset at 18:37. On the last day of September, in Iwakuni, sunrise is at 06:04 and sunset at 17:57 JST.

Sunshine

In Iwakuni, the average sunshine in September is 9.3h.

UV index

In Iwakuni, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for the ordinary person.
Note: In September, the maximum UV index of 5 suggests this advice:
Heed the precautions - Protecting the skin and eyes from damage is compulsory. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat.

Frequently asked questions

What is the usual temperature for Iwakuni in September?
September temperatures in Iwakuni vary between a high-temperature of 25.5°C (77.9°F) and a low-temperature of 19.7°C (67.5°F). The average heat index (a.k.a. 'felt air temperature', 'feels like'), which factors the actual air temperature with the relative humidity, in August is computed to be 36°C (96.8°F).
What is the average humidity in September in Iwakuni?
In September, the average relative humidity in Iwakuni is 80%.
How much does it rain in Iwakuni in September?
In Iwakuni, Japan, in September, it is raining for 13.9 days, with typically 47mm (1.85") of accumulated precipitation.
When it does not snow in Iwakuni?
In Iwakuni, Japan, snow does not fall in April through November.
How many hours of daylight does Iwakuni have in September?
In September, the average day length is 12h and 24min.
When are sunrise and sunset in September in Iwakuni?
In September, on the first day of the month, sunrise is at 05:44 and sunset at 18:37. On the last day of the month, in Iwakuni, sunrise is at 06:04 and sunset at 17:57 JST.
How many hours of sunshine does Iwakuni have in September?
The average sunshine duration in September in Iwakuni is 9.3h.
What is the UV index intensity in September in Iwakuni?
In September, the average daily maximum UV index in Iwakuni is 5. A UV Index value of 3 to 5 symbolizes a medium hazard to health from exposure to Sun's UV rays.
Average high temperature
Average low temperature
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility
Average temperature in September
Iwakuni, 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 (7.6°C).

  • Average low temperature in September: 19.7°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 (2.8°C).

Average pressure in September
Iwakuni, Japan
  • Average pressure in September: 1012.5mbar

The month with the highest atmospheric pressure is January (1021.2mbar).
The month with the lowest atmospheric pressure is June (1008.4mbar).

Average wind speed in September
Iwakuni, Japan
  • Average wind speed in September: 8km/h

The windiest month (with the highest average wind speed) is January (11.8km/h).
The calmest month (with the lowest average wind speed) is June (6.7km/h).

Average humidity in September
Iwakuni, Japan
  • Average humidity in September: 80%

The month with the highest relative humidity is July (86%).
The month with the lowest relative humidity is March (73%).

Average rainfall in September
Iwakuni, Japan
  • Average rainfall in September: 47mm

The wettest month (with the highest rainfall) is July (137mm).
The driest month (with the least rainfall) is November (24mm).

Average rainfall days in September
Iwakuni, Japan
  • Average rainfall days in September: 13.9 days

The month with the highest number of rainy days is July (20 days).
The month with the least rainy days is October (9.7 days).

Average snowfall in September
Iwakuni, Japan
  • Average snowfall in September: 0mm

The month with the highest snowfall is January (13mm).
The months with the least snowfall are April, May, June, July, August, September, October and November (0mm).

Average snowfall days in September
Iwakuni, Japan
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (4.8 days).
The months with the least snowfall days are April, May, June, July, August, September, October and November (0 days).

Average daylight in September /
Average sunshine in September
Iwakuni, 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: 9h and 2min

The month with the most sunshine is August (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 5h and 0min).

Average sunshine days in September
Iwakuni, Japan
  • Average sunshine days in September: 12.9 days

The month with the most sunshine days is May (19 days).
The month with the least sunshine days is July (8.8 days).

Average UV index in September
Iwakuni, 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
Iwakuni, Japan
  • Average cloud cover in September: 35

The months with the most cloud cover are January and June (Cloud cover 43).
The months with the least cloud cover are August and October (Cloud cover 31).

Average visibility in September
Iwakuni, Japan
  • Average visibility in September: 10km

The months with the highest visibility are January, February, March, September, October, November and December (10km).
The month with the lowest visibility is July (8km).

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