September weather forecast
Onslow, IA

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Weather in September

September, the first month of the autumn in Onslow, is still a pleasant month, with an average temperature fluctuating between 73°F (22.8°C) and 54.3°F (12.4°C).

Temperature

Onslow's transition into September involves a gentle shift in temperature, receding from a moderately hot 78.6°F (25.9°C) in August to an agreeable 73°F (22.8°C). An average temperature of 54.3°F (12.4°C) is recorded during the nights in September.

Humidity

The average relative humidity in September is 79%.

Rainfall

In Onslow, in September, during 11.4 rainfall days, 2.52" (64mm) of precipitation is typically accumulated. In Onslow, Iowa, during the entire year, the rain falls for 142.5 days and collects up to 28.27" (718mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

In September, the average length of the day in Onslow is 12h and 28min.
On the first day of September, sunrise is at 6:30 am and sunset at 7:37 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:46 pm CDT.

Sunshine

In September, the average sunshine in Onslow is 9.1h.

UV index

In Onslow, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for the average person.
Note: A typical high UV index of 4 in September suggests the following recommendations:
Exercise prudence. Persons with fair skin could be burned in under 30 minutes. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September in Onslow?

Onslow in September has an average high-temperature of 73°F (22.8°C) and an average low-temperature of 54.3°F (12.4°C).

What is the average humidity in September in Onslow?

The average relative humidity in September in Onslow, Iowa, is 79%.

How much does it rain in Onslow in September?

In Onslow, Iowa, during September, the rain falls for 11.4 days and regularly aggregates up to 2.52" (64mm) of precipitation.

When it does not snow in Onslow?

May through September are months without snowfall in Onslow.

Does it snow in Onslow in September?

In Onslow, in September, it doesn't snow. In October, it regularly snows.

How many hours of daylight does Onslow have in September?

In Onslow, the average day length in September is 12h and 28min.

What time are sunrise and sunset in September in Onslow?

In September, on the first day of the month, sunrise is at 6:30 am and sunset at 7:37 pm. On the last day of the month, in Onslow, Iowa, sunrise is at 7:00 am and sunset at 6:46 pm CDT.

How many hours of sunshine does Onslow have in September?

In September, the average sunshine duration in Onslow is 9.1h.

How high is the UV index in September in Onslow?

In Onslow, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate vulnerability from exposure to Sun's UV rays.
Average humidity
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
Onslow, IA

Average temperature in September - Onslow, IA
  • Average high temperature in September: 73°F

The warmest month (with the highest average high temperature) is July (80.1°F).
The month with the lowest average high temperature is January (25.2°F).

  • Average low temperature in September: 54.3°F

The month with the highest average low temperature is July (63.3°F).
The coldest month (with the lowest average low temperature) is January (13.3°F).

Average pressure in September
Onslow, IA

Average pressure in September - Onslow, IA
  • Average pressure in September: 30.02"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).

Average wind speed in September
Onslow, IA

Average wind speed in September - Onslow, IA
  • Average wind speed in September: 8mph

The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest month (with the lowest average wind speed) is August (6.9mph).

Average humidity in September
Onslow, IA

Average humidity in September - Onslow, IA
  • Average humidity in September: 79%

The months with the highest relative humidity are January and February (86%).
The month with the lowest relative humidity is October (74%).

Average rainfall in September
Onslow, IA

Average rainfall in September - Onslow, IA
  • Average rainfall in September: 2.52"

The wettest month (with the highest rainfall) is May (4.25").
The driest months (with the least rainfall) are January and February (1.26").

Average rainfall days in September
Onslow, IA

Average rainfall days in September - Onslow, IA
  • Average rainfall days in September: 11.4 days

The month with the highest number of rainy days is May (18.6 days).
The month with the least rainy days is January (5.2 days).

Average snowfall in September
Onslow, IA

Average snowfall in September - Onslow, IA
  • Average snowfall in September: 0"

The month with the highest snowfall is January (5.04").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Onslow, IA

Average snowfall days in September - Onslow, IA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (12.1 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Onslow, IA

Average daylight in September / Average sunshine in September - Onslow, IA
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in September: 9h and 1min

The months with the most sunshine are July and August (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).

Average sunshine days in September
Onslow, IA

Average sunshine days in September - Onslow, IA
  • Average sunshine days in September: 17 days

The month with the most sunshine days is September (17 days).
The month with the least sunshine days is June (10.5 days).

Average UV index in September
Onslow, IA

Average UV index in September - Onslow, IA
  • Average UV index in September: 4

The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).

Average cloud cover in September
Onslow, IA

Average cloud cover in September - Onslow, IA
  • Average cloud cover in September: 32

The month with the most cloud cover is January (Cloud cover 60).
The month with the least cloud cover is August (Cloud cover 30).

Average visibility in September
Onslow, IA

Average visibility in September - Onslow, IA
  • Average visibility in September: 6mi

The months with the highest visibility are February, March, April, May, June, August, September, October, November and December (6mi).
The months with the lowest visibility are January and July (5mi).

Onslow, Iowa, USA

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