Climate and monthly weather forecastRiley, OR
Climate and monthly weather forecast
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 »Updated: Aug 7, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
In Riley, during the entire year, the rain falls for 125.1 days and collects up to 11.26" (286mm) of precipitation.
January through March, November and December are months with snowfall.
In Riley, during the entire year, snow falls for 8.6 days and aggregates up to 1.97" (50mm) of snow.
The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2.
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.
April through October are months without snowfall.
With an average of 15h and 24min of daylight, June has the longest days of the year.
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).
The months with the lowest humidity are July and August, with an average relative humidity of 33%.
July is the month with the least rainfall. Rain falls for 3.7 days and accumulates 0.16" (4mm) of precipitation.
The month with the most sunshine is July, with an average of 12.1h of sunshine.
With an average maximum UV index of 7, July is the month with the highest UV index in Riley.
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.
December is the most humid month, with an average relative humidity of 83%.
December is the month with the most rainfall. Rain falls for 13.6 days and accumulates 1.54" (39mm) of precipitation.
December is the month with the most snowfall. Snow falls for 3.1 days and accumulates 0.87" (22mm) of snow.
With an average of 9h and 0min of daylight, December has the shortest days of the year.
December has the least sunshine of the year, with an average of 5.2h of sunshine.
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 in January:
30.22"Hg - Average pressure in February:
30.12"Hg - Average pressure in March:
30.04"Hg - Average pressure in April:
30.02"Hg - Average pressure in May:
29.96"Hg - Average pressure in June:
29.95"Hg
- Average pressure in July:
29.96"Hg - Average pressure in August:
29.94"Hg - Average pressure in September:
29.98"Hg - Average pressure in October:
30.06"Hg - Average pressure in November:
30.12"Hg - Average pressure in December:
30.19"Hg
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 in January:
7.7mph - Average wind speed in February:
8.9mph - Average wind speed in March:
9.8mph - Average wind speed in April:
9.9mph - Average wind speed in May:
9.3mph - Average wind speed in June:
8.9mph
- Average wind speed in July:
7.8mph - Average wind speed in August:
7.5mph - Average wind speed in September:
7.6mph - Average wind speed in October:
8mph - Average wind speed in November:
8.5mph - Average wind speed in December:
7.9mph
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
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 in January:
1.46" - Average rainfall in February:
1.3" - Average rainfall in March:
1.38" - Average rainfall in April:
1.3" - Average rainfall in May:
1.02" - Average rainfall in June:
0.71"
- Average rainfall in July:
0.16" - Average rainfall in August:
0.2" - Average rainfall in September:
0.47" - Average rainfall in October:
0.75" - Average rainfall in November:
0.98" - Average rainfall in December:
1.54"
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 in January:
12.8 days - Average rainfall days in February:
14.3 days - Average rainfall days in March:
17.7 days - Average rainfall days in April:
14.4 days - Average rainfall days in May:
11.9 days - Average rainfall days in June:
7.9 days
- Average rainfall days in July:
3.7 days - Average rainfall days in August:
3.3 days - Average rainfall days in September:
5.2 days - Average rainfall days in October:
9.2 days - Average rainfall days in November:
11.1 days - Average rainfall days in December:
13.6 days
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
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 in January:
2 days - Average snowfall days in February:
2.3 days - Average snowfall days in March:
0.5 days - Average snowfall days in April:
0 days - Average snowfall days in May:
0 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0 days - Average snowfall days in October:
0 days - Average snowfall days in November:
0.7 days - Average snowfall days in December:
3.1 days
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 in January:
9h and 24min - Average daylight in February:
10h and 30min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 30min - Average daylight in May:
14h and 42min - Average daylight in June:
15h and 24min
- Average daylight in July:
15h and 0min - Average daylight in August:
13h and 54min - Average daylight in September:
12h and 30min - Average daylight in October:
11h and 0min - Average daylight in November:
9h and 42min - Average daylight in December:
9h and 0min
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 January:
5h and 24min - Average sunshine in February:
5h and 24min - Average sunshine in March:
7h and 30min - Average sunshine in April:
10h and 6min - Average sunshine in May:
11h and 0min - Average sunshine in June:
11h and 30min
- Average sunshine in July:
12h and 6min - Average sunshine in August:
11h and 54min - Average sunshine in September:
10h and 54min - Average sunshine in October:
7h and 6min - Average sunshine in November:
6h and 24min - Average sunshine in December:
5h and 12min
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 in January:
15.7 days - Average sunshine days in February:
12.1 days - Average sunshine days in March:
11.5 days - Average sunshine days in April:
13.3 days - Average sunshine days in May:
16.5 days - Average sunshine days in June:
20.3 days
- Average sunshine days in July:
25.3 days - Average sunshine days in August:
25.3 days - Average sunshine days in September:
22.9 days - Average sunshine days in October:
20 days - Average sunshine days in November:
16.1 days - Average sunshine days in December:
14.5 days
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
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 cloud cover
Riley, OR
The month with the most cloud cover is December (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 9).
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).
