September weather forecast
John Day, OR

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The iconic Painted Hills in the famous John Day Fossil Beds National Monument, Oregon
The iconic Painted Hills in the famous John Day Fossil Beds National Monument, Oregon

Weather in September

With the commencement of September, the weather starts to transition into fall. Although the temperature drop is nominal, the observable difference is the increase in rainfall to 0.55" (14mm). The presence of early fall foliage starts to draw leaf-peepers. However, the wind picks up speed, and it mostly remains a mix of summer and fall. September in John Day, Oregon is known for its sunny days that lean into chiller nights.

Temperature

With September's onset, the weather shows a temperature decrease, transitioning from a warm 81°F (27.2°C) in August to an agreeable 71.2°F (21.8°C). Marked by a significant drop from the daytime highs, John Day's average low-temperature in September stands at a frosty 44.2°F (6.8°C).

Humidity

The average relative humidity in September is 51%.

Rainfall

In John Day, in September, it is raining for 6.6 days, with typically 0.55" (14mm) of accumulated precipitation. Throughout the year, there are 127.7 rainfall days, and 17.09" (434mm) of precipitation is accumulated.

Snowfall

January through May, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.08" (2mm) of snow. In John Day, during the entire year, snow falls for 62.5 days and aggregates up to 39.17" (995mm) of snow.

Daylight

The average length of the day in September is 12h and 30min.
On the first day of September, sunrise is at 6:19 am and sunset at 7:31 pm. On the last day of the month, sunrise is at 6:53 am and sunset at 6:37 pm PDT.

Sunshine

In September, the average sunshine is 10.7h.

UV index

The average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The UV index of 3 during September leads to these advisories:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses. Take precaution! The reflection from snow can almost double the UV radiation of the Sun.
Updated: Jul 26, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for John Day in September?

In September, the average high-temperature and low-temperature are 71.2°F (21.8°C) and 44.2°F (6.8°C) respectively. The average heat index (a.k.a. 'real feel', 'feels like'), which calculates the temperature value influenced by the moisture in the air, in August is computed to be 80.6°F (27°C).

What is the average humidity in September in John Day?

In John Day, the average relative humidity in September is 51%.

How many days does it rain in September?

In John Day, in September, during 6.6 rainfall days, 0.55" (14mm) of precipitation is typically accumulated.

When does it start snowing?

September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.08" (2mm) of snow.

What is the average length of the day in September?

In September, the average day length is 12h and 30min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 6:19 am and sunset at 7:31 pm. On the last day of the month, sunrise is at 6:53 am and sunset at 6:37 pm PDT.

How long on average sun shines in September?

The average sunshine duration in September is 10.7h.

How high is the UV index in September?

In John Day, Oregon, the average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a moderate health threat 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
John Day, OR

Average temperature in September - John Day, OR
  • Average high temperature in September: 71.2°F

The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is December (33.4°F).

  • Average low temperature in September: 44.2°F

The month with the highest average low temperature is August (49.6°F).
The coldest month (with the lowest average low temperature) is December (19.6°F).

Average pressure in September
John Day, OR

Average pressure in September - John Day, OR
  • Average pressure in September: 29.97"Hg

The month with the highest atmospheric pressure is January (30.22"Hg).
The month with the lowest atmospheric pressure is August (29.93"Hg).

Average wind speed in September
John Day, OR

Average wind speed in September - John Day, OR
  • Average wind speed in September: 5mph

The windiest month (with the highest average wind speed) is April (6.2mph).
The calmest months (with the lowest average wind speed) are August and September (5mph).

Average humidity in September
John Day, OR

Average humidity in September - John Day, OR
  • Average humidity in September: 51%

The month with the highest relative humidity is February (85%).
The month with the lowest relative humidity is August (42%).

Average rainfall in September
John Day, OR

Average rainfall in September - John Day, OR
  • Average rainfall in September: 0.55"

The wettest month (with the highest rainfall) is February (2.28").
The driest month (with the least rainfall) is July (0.24").

Average rainfall days in September
John Day, OR

Average rainfall days in September - John Day, OR
  • Average rainfall days in September: 6.6 days

The month with the highest number of rainy days is March (17.3 days).
The month with the least rainy days is August (3.3 days).

Average snowfall in September
John Day, OR

Average snowfall in September - John Day, OR
  • Average snowfall in September: 0.08"

The month with the highest snowfall is February (10.31").
The months with the least snowfall are June, July and August (0").

Average snowfall days in September
John Day, OR

Average snowfall days in September - John Day, OR
  • Average snowfall days in September: 0.2 days

The month with the highest number of snowfall days is December (14.5 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in September /
Average sunshine in September
John Day, OR

Average daylight in September / Average sunshine in September - John Day, 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: 10h and 4min

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

Average sunshine days in September
John Day, OR

Average sunshine days in September - John Day, OR
  • Average sunshine days in September: 21.8 days

The month with the most sunshine days is July (24.9 days).
The month with the least sunshine days is February (9 days).

Average UV index in September
John Day, OR

Average UV index in September - John Day, OR
  • Average UV index in September: 3

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
John Day, OR

Average cloud cover in September - John Day, OR
  • Average cloud cover in September: 17

The month with the most cloud cover is February (Cloud cover 49).
The months with the least cloud cover are July and August (Cloud cover 9).

Average visibility in September
John Day, OR

Average visibility in September - John Day, OR
  • Average visibility in September: 6mi

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

John Day, Oregon, USA

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