Climate and monthly weather forecast
Riley, OR

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Weather in January

January, the same as December, is another cold winter month in Riley, Oregon, with an average temperature fluctuating between 34.9°F (1.6°C) and 22.3°F (-5.4°C). January records an average high-temperature of a still cold 34.9°F (1.6°C), indicating a minor variation from the preceding month. Weather in January »

Weather in February

February, the last month of the winter in Riley, is also an icy month, with temperature in the range of an average low of 24.6°F (-4.1°C) and an average high of 37.4°F (3°C). As February takes its course, Riley's average high-temperature registers at a still wintry 37.4°F (3°C), closely aligning with the preceding month. Weather in February »

Weather in March

The first month of the spring, March, is a frosty month in Riley, Oregon, with an average temperature ranging between max 44.8°F (7.1°C) and min 30.6°F (-0.8°C). Riley in March experiences a slight uptick in the average high-temperature, adjusting from February's wintry 37.4°F (3°C) to a chilly 44.8°F (7.1°C). Weather in March »

Weather in April

April in Riley, Oregon, is a fresh spring month, with an average temperature varying between 34.3°F (1.3°C) and 52.2°F (11.2°C). The shift from March to April sees a slight increase in the average high-temperature, transitioning from a frosty 44.8°F (7.1°C) to a cool 52.2°F (11.2°C). Weather in April »

Weather in May

May, the last month of the spring in Riley, is a refreshing month, with an average temperature fluctuating between 62.4°F (16.9°C) and 42.1°F (5.6°C). May comes with an increase, with the average high-temperature moving from a cool 52.2°F (11.2°C) in April to a comfortable 62.4°F (16.9°C). Weather in May »

Weather in June

June, the first month of the summer in Riley, is an agreeable month, with an average temperature fluctuating between 48.7°F (9.3°C) and 71.2°F (21.8°C). Entering June, Riley notices a subtle temperature elevation, with the average high-temperature advancing from May's enjoyable 62.4°F (16.9°C) to an agreeable 71.2°F (21.8°C). Weather in June »

Weather in July

July is a moderately hot summer month in Riley, Oregon, with temperature in the range of an average high of 82.9°F (28.3°C) and an average low of 57.4°F (14.1°C). July proves to be the warmest month, recording an average peak temperature of 82.9°F (28.3°C) and a minimum temperature of 57.4°F (14.1°C). Weather in July »

Weather in August

August, the last month of the summer in Riley, is also a moderately hot month, with an average temperature varying between 58.1°F (14.5°C) and 81.9°F (27.7°C). As July transitions into August, the average high-temperature rests at a still moderately hot 81.9°F (27.7°C), maintaining a close resemblance to the previous month. Weather in August »

Weather in September

The first month of the autumn, September, is still a pleasant month in Riley, Oregon, with an average temperature fluctuating between 51.1°F (10.6°C) and 72.3°F (22.4°C). Riley, Oregon, in September demonstrates a small temperature transition, adjusting from an average high of a moderately hot 81.9°F (27.7°C) in August to an agreeable 72.3°F (22.4°C). Weather in September »

Weather in October

October, the same as September, in Riley, Oregon, is a moderate autumn month, with an average temperature ranging between min 39.4°F (4.1°C) and max 56.7°F (13.7°C). October's arrival signals a distinct temperature shift, dropping from a pleasant 72.3°F (22.4°C) in September to a mild 56.7°F (13.7°C). Weather in October »

Weather in November

The last month of the autumn, November, is also a frosty month in Riley, Oregon, with temperature in the range of an average low of 29.3°F (-1.5°C) and an average high of 43.5°F (6.4°C). Transition into November marks a drop in the average high-temperature, moving from a moderate 56.7°F (13.7°C) in October to a chilly 43.5°F (6.4°C). Weather in November »

Weather in December

December, the first month of the winter in Riley, is also an icy month, with an average temperature ranging between max 33.1°F (0.6°C) and min 21.2°F (-6°C). With average high and low temperatures of 33.1°F (0.6°C) and 21.2°F (-6°C) respectively, December is Riley's coldest month. Weather in December »

Frequently asked questions

How many days does it rain?

In Riley, during the entire year, the rain falls for 125.1 days and collects up to 11.26" (286mm) of precipitation.

When does it snow?

January through March, November and December are months with snowfall.

How much does it snow?

In Riley, during the entire year, snow falls for 8.6 days and aggregates up to 1.97" (50mm) of snow.

What are the months with the lowest UV index?

The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2.

When is Daylight Saving Time (DST)?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from PST to PDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from PDT to PST.

When it does not snow?

April through October are months without snowfall.

When are the longest days?

With an average of 15h and 24min of daylight, June has the longest days of the year.

What are the warmest months?

Riley's warmest month, July, registers temperatures that range from a high of 82.9°F (28.3°C) to a low of 57.4°F (14.1°C).

What are the least humid months?

The months with the lowest humidity are July and August, with an average relative humidity of 33%.

What is the driest month?

July is the month with the least rainfall. Rain falls for 3.7 days and accumulates 0.16" (4mm) of precipitation.

What month has the most sunshine?

The month with the most sunshine is July, with an average of 12.1h of sunshine.

When is the highest UV index?

With an average maximum UV index of 7, July is the month with the highest UV index in Riley.

What month is the coldest?

With an average high-temperature of 33.1°F (0.6°C) and an average low-temperature of 21.2°F (-6°C), December is the coldest month.

What is the most humid month?

December is the most humid month, with an average relative humidity of 83%.

What is the wettest month?

December is the month with the most rainfall. Rain falls for 13.6 days and accumulates 1.54" (39mm) of precipitation.

When does it snow the most?

December is the month with the most snowfall. Snow falls for 3.1 days and accumulates 0.87" (22mm) of snow.

What is the month with the shortest days?

With an average of 9h and 0min of daylight, December has the shortest days of the year.

What is the month with the least sunshine?

December has the least sunshine of the year, with an average of 5.2h of sunshine.

Average temperature
Riley, OR

Average temperature - Riley, OR

The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is December (33.1°F).

The month with the highest average low temperature is August (58.1°F).
The coldest month (with the lowest average low temperature) is December (21.2°F).

Average pressure
Riley, OR

Average pressure - Riley, OR

The month with the highest atmospheric pressure is January (30.22"Hg).
The month with the lowest atmospheric pressure is August (29.94"Hg).

Average wind speed
Riley, OR

Average wind speed - Riley, OR

The windiest month (with the highest average wind speed) is April (9.9mph).
The calmest month (with the lowest average wind speed) is August (7.5mph).

Average humidity
Riley, OR

Average humidity - Riley, OR

The month with the highest relative humidity is December (83%).
The months with the lowest relative humidity are July and August (33%).

Average rainfall
Riley, OR

Average rainfall - Riley, OR

The wettest month (with the highest rainfall) is December (1.54").
The driest month (with the least rainfall) is July (0.16").

Average rainfall days
Riley, OR

Average rainfall days - Riley, OR

The month with the highest number of rainy days is March (17.7 days).
The month with the least rainy days is August (3.3 days).

Average snowfall
Riley, OR

Average snowfall - Riley, OR

The month with the highest snowfall is December (0.87").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days
Riley, OR

Average snowfall days - Riley, OR

The month with the highest number of snowfall days is December (3.1 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

Average daylight / Average sunshine
Riley, OR

Average daylight / Average sunshine - Riley, OR

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).

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 12min).

Average sunshine days
Riley, OR

Average sunshine days - Riley, OR

The months with the most sunshine days are July and August (25.3 days).
The month with the least sunshine days is March (11.5 days).

Average UV index
Riley, OR

Average UV index - Riley, OR

The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, March, November and December (UV index 2).

Average visibility
Riley, OR

Average visibility - Riley, OR

The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).

Riley, Oregon, USA

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