September weather forecast
La Grande, OR

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Weather in September

The first month of the autumn, September, is still a pleasant month in La Grande, Oregon, with an average temperature fluctuating between 72.1°F (22.3°C) and 46°F (7.8°C).

Temperature

The move into September indicates a reduction in the average high-temperature, down from August's moderately hot 81.3°F (27.4°C) to a pleasant 72.1°F (22.3°C). La Grande notes a substantial temperature decline from the daytime peaks throughout September, with an average nighttime temperature of 46°F (7.8°C).

Humidity

In September, the average relative humidity is 52%.

Rainfall

In La Grande, during September, the rain falls for 6.5 days and regularly aggregates up to 0.67" (17mm) of precipitation. In La Grande, during the entire year, the rain falls for 141.7 days and collects up to 18.43" (468mm) 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 0.2 snowfall days, it receives 0.04" (1mm) of snow. Throughout the year, there are 56.6 snowfall days, and 36.85" (936mm) of snow is accumulated.

Daylight

In La Grande, the average length of the day in September is 12h and 31min.
On the first day of September, sunrise is at 6:15 am and sunset at 7:29 pm. On the last day of the month, sunrise is at 6:50 am and sunset at 6:33 pm PDT.

Sunshine

In La Grande, the average sunshine in September is 10.6h.

UV index

In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for the average person.
Note: The average daily UV index of 4 in September transforms into the following instructions:
Adopt protective measures - Requirement to safeguard skin and eyes from harm exists. Exposing oneself to the midday Sun can be harmful due to the strong UV radiation; limit your time outside. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.

Frequently asked questions

What is the usual temperature for La Grande in September?

During September, La Grande experiences an average high-temperature of 72.1°F (22.3°C) and a low-temperature of 46°F (7.8°C). In August, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which combines air temperature and relative humidity, is calculated to be 80.6°F (27°C).

What is the average humidity in September?

The average relative humidity in September is 52%.

How many days does it rain in September in La Grande?

In September, the rain falls for 6.5 days. Throughout September, 0.67" (17mm) of precipitation is accumulated.

When does it start to snow?

September is the first month it typically snows in La Grande. Throughout September, in the average 0.2 snowfall days, it receives 0.04" (1mm) of snow.

What is the average length of the day in September?

In September, the average day length is 12h and 31min.

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 6:15 am and sunset at 7:29 pm. On the last day of the month, sunrise is at 6:50 am and sunset at 6:33 pm PDT.

How long on average sun shines in September?

In September, the average sunshine duration is 10.6h.

What is the UV index intensity in September?

In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a moderate health threat from exposure to the Sun's UV radiation.
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
La Grande, OR

Average temperature in September - La Grande, OR
  • Average high temperature in September: 72.1°F

The warmest month (with the highest average high temperature) is August (81.3°F).
The month with the lowest average high temperature is December (32.5°F).

  • Average low temperature in September: 46°F

The month with the highest average low temperature is August (52.2°F).
The coldest month (with the lowest average low temperature) is December (20.5°F).

Average pressure in September
La Grande, OR

Average pressure in September - La Grande, OR
  • Average pressure in September: 29.96"Hg

The month with the highest atmospheric pressure is January (30.22"Hg).
The month with the lowest atmospheric pressure is August (29.92"Hg).

Average wind speed in September
La Grande, OR

Average wind speed in September - La Grande, OR
  • Average wind speed in September: 4.6mph

The windiest month (with the highest average wind speed) is January (7.1mph).
The calmest month (with the lowest average wind speed) is August (4.4mph).

Average humidity in September
La Grande, OR

Average humidity in September - La Grande, OR
  • Average humidity in September: 52%

The months with the highest relative humidity are January and February (86%).
The month with the lowest relative humidity is August (45%).

Average rainfall in September
La Grande, OR

Average rainfall in September - La Grande, OR
  • Average rainfall in September: 0.67"

The wettest month (with the highest rainfall) is December (2.48").
The driest month (with the least rainfall) is July (0.35").

Average rainfall days in September
La Grande, OR

Average rainfall days in September - La Grande, OR
  • Average rainfall days in September: 6.5 days

The month with the highest number of rainy days is March (17.3 days).
The month with the least rainy days is August (4.8 days).

Average snowfall in September
La Grande, OR

Average snowfall in September - La Grande, OR
  • Average snowfall in September: 0.04"

The month with the highest snowfall is February (10.2").
The months with the least snowfall are June, July and August (0").

Average snowfall days in September
La Grande, OR

Average snowfall days in September - La Grande, OR
  • Average snowfall days in September: 0.2 days

The month with the highest number of snowfall days is December (13.2 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in September /
Average sunshine in September
La Grande, OR

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

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in September: 10h and 4min

The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The months with the least sunshine are January and February (Average sunshine: 5h and 6min).

Average sunshine days in September
La Grande, OR

Average sunshine days in September - La Grande, OR
  • Average sunshine days in September: 21.6 days

The month with the most sunshine days is July (23.4 days).
The month with the least sunshine days is February (9.1 days).

Average UV index in September
La Grande, OR

Average UV index in September - La Grande, 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, March, April, November and December (UV index 2).

Average cloud cover in September
La Grande, OR

Average cloud cover in September - La Grande, OR
  • Average cloud cover in September: 17

The month with the most cloud cover is February (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 10).

Average visibility in September
La Grande, OR

Average visibility in September - La Grande, OR
  • 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, February and December (5mi).

La Grande, Oregon, USA

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