September weather forecast
Lebanon, OR

Share

Weather in September

Fall starts to make its presence known in September in Lebanon, as the weather starts cooling down. From 81.1°F (27.3°C) in August, a downturn in average high temperatures is noticeable, dropping to 73.4°F (23°C). Besides the temperature, the sunshine duration also dwindles, giving way to longer nights. Though the rainfall sees an increase, it continues to remain on the lower side compared to other months. In essence, September brings a subtle shift in climate as it marks the transition from summer to fall.

Temperature

September's arrival aligns with a minor decrease in average high-temperatures, from August's warm 81.1°F (27.3°C) to a still moderately hot 73.4°F (23°C). September nights see a notable contrast from daytime highs, with the nighttime temperature averaging at a frosty 48.9°F (9.4°C).

Humidity

In Lebanon, the average relative humidity in September is 71%.

Rainfall

In Lebanon, during September, the rain falls for 8.8 days and regularly aggregates up to 1.5" (38mm) of precipitation. In Lebanon, during the entire year, the rain falls for 163.3 days and collects up to 29.92" (760mm) of precipitation.

Snowfall

In Lebanon, snow does not fall in April through October.

Daylight

In Lebanon, the average length of the day in September is 12h and 30min.
On the first day of the month, sunrise is at 6:35 am and sunset at 7:47 pm. On the last day of September, sunrise is at 7:09 am and sunset at 6:53 pm PDT.

Sunshine

The average sunshine in September in Lebanon is 9.4h.

UV index

In Lebanon, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the ordinary person.
Note: The daily maximum UV index of 4 in September interprets into the following advice:
Heed the precautions - It is counselled to guard against solar damage. The solar radiation around mid-day is intense; avoid the Sun and stay safe. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Updated: Aug 29, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature?

The high-temperature during September is 73.4°F (23°C) and the low-temperature is 48.9°F (9.4°C). The average heat index (a.k.a. 'real feel', 'apparent temperature'), which represents the influence of relative humidity on air temperature, in August is estimated at 84.2°F (29°C).

What is the average humidity in September?

In Lebanon, the average relative humidity in September is 71%.

How much does it rain in September?

In Lebanon, during September, the rain falls for 8.8 days and regularly aggregates up to 1.5" (38mm) of precipitation.

When it does not snow?

In Lebanon, snow does not fall in April through October.

What is the average length of the day in September?

The average day length in September is 12h and 30min.

When are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:35 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 7:09 am and sunset at 6:53 pm PDT.

How long on average sun shines in September?

In Lebanon, the average sunshine duration in September is 9.4h.

What is the UV index reading in September in Lebanon?

In Lebanon, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate vulnerability from unprotected exposure to 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
Lebanon, OR

Average temperature in September - Lebanon, OR
  • Average high temperature in September: 73.4°F

The warmest month (with the highest average high temperature) is August (81.1°F).
The month with the lowest average high temperature is December (45.3°F).

  • Average low temperature in September: 48.9°F

The month with the highest average low temperature is August (51.8°F).
The coldest month (with the lowest average low temperature) is December (34.2°F).

Average pressure in September
Lebanon, OR

Average pressure in September - Lebanon, OR
  • Average pressure in September: 30.01"Hg

The month with the highest atmospheric pressure is January (30.12"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).

Average wind speed in September
Lebanon, OR

Average wind speed in September - Lebanon, OR
  • Average wind speed in September: 4mph

The windiest months (with the highest average wind speed) are January and March (5.1mph).
The calmest month (with the lowest average wind speed) is August (3.9mph).

Average humidity in September
Lebanon, OR

Average humidity in September - Lebanon, OR
  • Average humidity in September: 71%

The months with the highest relative humidity are January, February, March and December (86%).
The month with the lowest relative humidity is August (66%).

Average rainfall in September
Lebanon, OR

Average rainfall in September - Lebanon, OR
  • Average rainfall in September: 1.5"

The wettest month (with the highest rainfall) is December (4.41").
The driest month (with the least rainfall) is July (0.24").

Average rainfall days in September
Lebanon, OR

Average rainfall days in September - Lebanon, OR
  • Average rainfall days in September: 8.8 days

The month with the highest number of rainy days is March (20.1 days).
The months with the least rainy days are July and August (3.8 days).

Average snowfall in September
Lebanon, OR

Average snowfall in September - Lebanon, OR
  • Average snowfall in September: 0"

The month with the highest snowfall is February (2.13").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in September
Lebanon, OR

Average snowfall days in September - Lebanon, OR
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (2.5 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average daylight in September /
Average sunshine in September
Lebanon, OR

Average daylight in September / Average sunshine in September - Lebanon, OR
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is August (Average sunshine: 11h and 12min).
The month with the least sunshine is February (Average sunshine: 4h and 12min).

Average sunshine days in September
Lebanon, OR

Average sunshine days in September - Lebanon, OR
  • Average sunshine days in September: 19.3 days

The month with the most sunshine days is July (25.6 days).
The month with the least sunshine days is March (9.1 days).

Average UV index in September
Lebanon, OR

Average UV index in September - Lebanon, OR
  • 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, November and December (UV index 2).

Average cloud cover in September
Lebanon, OR

Average cloud cover in September - Lebanon, OR
  • Average cloud cover in September: 30

The month with the most cloud cover is February (Cloud cover 59).
The month with the least cloud cover is August (Cloud cover 20).

Average visibility in September
Lebanon, OR

Average visibility in September - Lebanon, OR
  • Average visibility in September: 6mi

The months with the highest visibility are July, August and September (6mi).
The month with the lowest visibility is February (4mi).

Lebanon, Oregon, USA

Weather forecast for your location

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