September weather forecast
Iona, ID

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Weather in September

The first month of the autumn, September, is also a moderately hot month in Iona, Idaho, with temperature in the range of an average low of 49.5°F (9.7°C) and an average high of 73.6°F (23.1°C).

Temperature

With the onset of September, Iona's average high-temperature adjusts, receding from August's 84.4°F (29.1°C) to a still warm 73.6°F (23.1°C). Iona, amid September nights, sees a noteworthy disparity from daily highs with an average temperature of 49.5°F (9.7°C).

Humidity

The average relative humidity in September is 41%.

Rainfall

The wettest months are May and September, with an average 0.83" (21mm) of rainfall.

Snowfall

Months with snowfall are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.04" (1mm) of snow. In Iona, Idaho, during the entire year, snow falls for 54.4 days and aggregates up to 16.89" (429mm) of snow.

Daylight

The average length of the day in September is 12h and 29min.
On the first day of the month, sunrise is at 6:52 am and sunset at 8:02 pm. On the last day of September, sunrise is at 7:25 am and sunset at 7:09 pm MDT.

Sunshine

The average sunshine in September is 10h.

UV index

In Iona, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: A maximum daily UV index of 4 during September morphs into the following directions:
Make use of precautions - Suggestions to resist sunburn are communicated. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly. Be cautious! The UV radiation from the Sun can be magnified almost twofold by snow reflection.

Frequently asked questions

What are September temperatures?

September temperatures vary between a high-temperature of 73.6°F (23.1°C) and a low-temperature of 49.5°F (9.7°C).

What is the average humidity in September?

The average relative humidity in September is 41%.

What is the wettest month?

The months with the most rainfall are May and September, with an average 0.83" (21mm) of precipitation.

How many days does it rain in September?

In September, the rain falls for 8.1 days. Throughout September, 0.83" (21mm) of precipitation is accumulated.

When does it start to snow?

September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.04" (1mm) of snow.

What is the average length of the day in September?

The average day length in September is 12h and 29min.

When are sunrise and sunset in September in Iona?

In September, on the first day of the month, sunrise is at 6:52 am and sunset at 8:02 pm. On the last day of the month, sunrise is at 7:25 am and sunset at 7:09 pm MDT.

How long on average sun shines in September?

In September, the average sunshine duration is 10h.

What is the UV index reading in September?

The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate vulnerability from exposure to the Sun's UV radiation.
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
Iona, ID

Average temperature in September - Iona, ID
  • Average high temperature in September: 73.6°F

The warmest month (with the highest average high temperature) is July (86.2°F).
The month with the lowest average high temperature is December (27.9°F).

  • Average low temperature in September: 49.5°F

The month with the highest average low temperature is August (54.3°F).
The coldest month (with the lowest average low temperature) is January (14.2°F).

Average pressure in September
Iona, ID

Average pressure in September - Iona, ID
  • Average pressure in September: 29.98"Hg

The month with the highest atmospheric pressure is January (30.3"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
Iona, ID

Average wind speed in September - Iona, ID
  • Average wind speed in September: 7.6mph

The windiest month (with the highest average wind speed) is April (9mph).
The calmest month (with the lowest average wind speed) is January (5.8mph).

Average humidity in September
Iona, ID

Average humidity in September - Iona, ID
  • Average humidity in September: 41%

The month with the highest relative humidity is January (90%).
The month with the lowest relative humidity is August (35%).

Average rainfall in September
Iona, ID

Average rainfall in September - Iona, ID
  • Average rainfall in September: 0.83"

The wettest months (with the highest rainfall) are May and September (0.83").
The driest month (with the least rainfall) is July (0.35").

Average rainfall days in September
Iona, ID

Average rainfall days in September - Iona, ID
  • Average rainfall days in September: 8.1 days

The month with the highest number of rainy days is May (10.7 days).
The month with the least rainy days is January (3.7 days).

Average snowfall in September
Iona, ID

Average snowfall in September - Iona, ID
  • Average snowfall in September: 0.04"

The month with the highest snowfall is January (3.86").
The months with the least snowfall are June, July and August (0").

Average snowfall days in September
Iona, ID

Average snowfall days in September - Iona, ID
  • Average snowfall days in September: 0.1 days

The month with the highest number of snowfall days is December (12.9 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in September /
Average sunshine in September
Iona, ID

Average daylight in September / Average sunshine in September - Iona, ID
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).

  • Average sunshine in September: 10h and 0min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is January (Average sunshine: 4h and 42min).

Average sunshine days in September
Iona, ID

Average sunshine days in September - Iona, ID
  • Average sunshine days in September: 19.4 days

The month with the most sunshine days is October (22.1 days).
The month with the least sunshine days is February (16.2 days).

Average UV index in September
Iona, ID

Average UV index in September - Iona, ID
  • Average UV index in September: 4

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).

Average cloud cover in September
Iona, ID

Average cloud cover in September - Iona, ID
  • Average cloud cover in September: 16

The months with the most cloud cover are January and February (Cloud cover 51).
The months with the least cloud cover are July and August (Cloud cover 11).

Average visibility in September
Iona, ID

Average visibility in September - Iona, ID
  • Average visibility in September: 6mi

The months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and February (4mi).

Iona, Idaho, USA

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