September weather forecast
Lewisville, ID

Share

Weather in September

The first month of the autumn, September, is still a pleasant month in Lewisville, Idaho, with an average temperature varying between 47.8°F (8.8°C) and 72.9°F (22.7°C).

Temperature

The average high-temperature drops in September, from August's warm 83.3°F (28.5°C) to an agreeable 72.9°F (22.7°C). Despite the hot September days, Lewisville's nights see an average temperature plunge to a chilly 47.8°F (8.8°C).

Humidity

In Lewisville, the average relative humidity in September is 42%.

Rainfall

In Lewisville, in September, during 7.8 rainfall days, 0.83" (21mm) of precipitation is typically accumulated. In Lewisville, during the entire year, the rain falls for 112.3 days and collects up to 10.94" (278mm) of precipitation.

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 0.24" (6mm) of snow. Throughout the year, there are 79 snowfall days, and 31.54" (801mm) of snow is accumulated.

Daylight

The average length of the day in September is 12h and 29min.
On the first day of September, 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 7:10 pm MDT.

Sunshine

In Lewisville, Idaho, the average sunshine in September is 10h.

UV index

In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the average person.
Note: The maximum daily UV index of 4 in September converts into the following recommendations:
Put precautions into practice - Protective measures against sun-induced damage are advised. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses. Be vigilant! The reflective nature of snow can increase the Sun's UV radiation nearly twofold.
Updated: Aug 17, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Lewisville in September?

September temperatures vary between a high-temperature of 72.9°F (22.7°C) and a low-temperature of 47.8°F (8.8°C).

What is the average humidity in September?

In Lewisville, the average relative humidity in September is 42%.

How much does it rain in September?

In September, the rain falls for 7.8 days. Throughout September, 0.83" (21mm) of precipitation is accumulated.

When does it start snowing?

September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.24" (6mm) of snow.

What is the average length of the day in September?

In Lewisville, the average day length in September is 12h and 29min.

When is the sunrise / sunset in September?

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 7:10 pm MDT.

How long on average sun shines in September?

The average sunshine duration in September is 10h.

How high is the UV index in September?

In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium hazard to health from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Lewisville, ID

Average temperature in September - Lewisville, ID
  • Average high temperature in September: 72.9°F

The warmest month (with the highest average high temperature) is July (85.1°F).
The month with the lowest average high temperature is December (27.1°F).

  • Average low temperature in September: 47.8°F

The month with the highest average low temperature is August (53.8°F).
The coldest month (with the lowest average low temperature) is January (13.8°F).

Average pressure in September
Lewisville, ID

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

The month with the highest atmospheric pressure is January (30.29"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
Lewisville, ID

Average wind speed in September - Lewisville, ID
  • Average wind speed in September: 6.8mph

The windiest month (with the highest average wind speed) is April (8mph).
The calmest month (with the lowest average wind speed) is January (4.9mph).

Average humidity in September
Lewisville, ID

Average humidity in September - Lewisville, ID
  • Average humidity in September: 42%

The month with the highest relative humidity is January (90%).
The month with the lowest relative humidity is August (37%).

Average rainfall in September
Lewisville, ID

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

The wettest month (with the highest rainfall) is May (1.26").
The driest month (with the least rainfall) is July (0.31").

Average rainfall days in September
Lewisville, ID

Average rainfall days in September - Lewisville, ID
  • Average rainfall days in September: 7.8 days

The month with the highest number of rainy days is April (14.2 days).
The month with the least rainy days is July (5.8 days).

Average snowfall in September
Lewisville, ID

Average snowfall in September - Lewisville, ID
  • Average snowfall in September: 0.24"

The month with the highest snowfall is January (8.31").
The months with the least snowfall are June, July and August (0").

Average snowfall days in September
Lewisville, ID

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

The month with the highest number of snowfall days is January (17.3 days).
The months with the least snowfall days are July and August (0 days).

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

Average daylight in September / Average sunshine in September - Lewisville, 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: 12h and 0min).
The month with the least sunshine is January (Average sunshine: 4h and 42min).

Average sunshine days in September
Lewisville, ID

Average sunshine days in September - Lewisville, ID
  • Average sunshine days in September: 19.8 days

The month with the most sunshine days is July (22.3 days).
The month with the least sunshine days is February (9.9 days).

Average UV index in September
Lewisville, ID

Average UV index in September - Lewisville, 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 and December (UV index 1).

Average cloud cover in September
Lewisville, ID

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

The month with the most cloud cover is February (Cloud cover 52).
The months with the least cloud cover are July and August (Cloud cover 11).

Average visibility in September
Lewisville, ID

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

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

Lewisville, Idaho, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location