Monthly weather forecast and climate
Oregon, USA

Flag of Oregon, USA
Flag of Oregon, USA

The climate of Oregon

Oregon lies in the Pacific Northwest region and has a diverse geography that consists of numerous water bodies, deserts, shrublands, dense forests, mountains, and volcanoes. California in the south, the Pacific Ocean in the west, Washington in the north, Idaho in the east, and Nevada in the southeast share borders with the state. Western Oregon along the coast has an oceanic climate (Köppen climate classification Cfb) with wet summers, while the southwestern portion of the state has a Mediterranean (Köppen Csb) climate with hot summers; The northeastern portion has a steppe climate with subarctic (Köppen Dsc) conditions at high altitude, and the rest of the east is semi-arid (Köppen BSk) with cold and snowy winters. The Pacific Ocean has a significant influence on the climate that keeps the temperatures mild in comparison with places at similar latitudes.

Oregon, the Beaver State's topography ranges from rain forests along the western coast to semi-arid conditions in the central and southeastern regions. Mount Hood is the highest peak in the state, while Columbia is the most important river that flows through the Cascade Mountains. The three mountain ranges: Coast, Cascade, and the Blue Mountains influence the climate in the parts of the state that lie in their proximity. The river valleys have the most fertile agricultural lands, while mountains and plateaus provide for dry farming and livestock grazing. The arid Columbia plateau covers two-thirds of the total area of the state with elevations ranging from 1500 to 2000 meters.

Oregon registers wide variation in temperatures across four seasons. Summer high temperatures average 64°F (17.8°C) to 68°F (20°C) in July on the west coast, while they range between 81°F (27.2°C) to 94°F (34.4°C) in the eastern portion of the state. The average low temperatures in the winter hit 18°F (-7.8°C) in January in the Cascade Mountains, while they register in the mild 37°F (2.8°C) to 42°F (5.6°C) range in the coastal region. Spring is mild and wet in many parts of the state except for places like Crater Lake, where the nights are below freezing. Autumn is pleasant and colorful, with day temperatures exceeding 55°F (12.8°C) in October.

Rainfall in Oregon varies considerably from the west coast to the central and eastern regions. The coast registers 80" (2032mm) to 90" (2286mm) of rain annually, which increases up to 200" (5080mm) on the western slopes of the Coast Range. The average precipitation on the plateau region is a mere 8" (203mm), while the eastern slopes of the mountains receive 15" (381mm) to 20" (508mm) of annual rainfall. Average annual snowfall ranges from 2" (51mm) along the coast to 12" (305mm) in the inland valleys. Central Oregon registers 20" (508mm) of snow, while the eastern portion records 55" (1397mm). The mountain ranges record a massive 150" (3810mm) to 550" (13970mm) of snow with the heaviest snowfall in the Cascade Mountains. Portland, the capital of Oregon, records 142 sunny days in the year.

Pendleton in Oregon recorded the highest ever temperature of 119°F (48.3°C) on August 10, 1898, while Seneca recorded the coldest temperature of -54°F (-47.8°C) on February 10, 1933.

The best time to visit Oregon

The best time to visit Oregon is during the summer from June to August when the weather is relatively dry. Wildflowers are in full bloom by July even in the upper reaches of the mountain ranges. Late spring has mild conditions, but the weather is unpredictable. Early autumn in September often has good weather along the coast. The Coast Range has a relatively mild climate due to the influence of the Pacific Ocean, while the central and eastern parts register temperatures above 100°F (37.8°C).

The worst time to visit Oregon

The worst time to visit Oregon is from December to February in the winter. Winter is snowy in the mountains, especially the high elevations of the Cascade, Blue and Wallowa mountains. The majority of the rainfall occurs from October to May with a peak during the cold season. Heavy and persistent snowfall results in significant snow depth that serves as a major attraction during the skiing season. Snowstorms frequently strike the mountains and may last more than 24 hours. Winter skies are gray with frequent blasts of arctic air.

Weather hazards

Oregon is vulnerable to hailstorms, thunderstorms, wildfires, snowstorms, hurricanes, and floods. Hailstorms are common on the eastern side of the Cascade Mountains and cause damage to crops. Thunderstorms with lightning occur 10 to 15 days annually in the mountain areas with a heightened risk of forest fires. Hurricane-force winds strike the Oregon coast several times in the year, occasionally move inland and cause destruction of power lines. Flooding is frequent in late spring and summer in the Willamette and Columbia river basins due to rain and melting of snow. Snowstorms occur in winter in the high mountain ranges.

Weather in January

January is the coldest month of the year in Oregon with gray skies and abundant snowfall in the high mountains. The average low temperatures across the state are between 11°F (-11.7°C) to 42°F (5.6°C), while the average high temperatures lie in the 34°F (1.1°C) to 55°F (12.8°C) range. Weather in January »

Weather in February

February is chilly in Oregon as the winter brings cold winds along with precipitation and snowfall to the state. Day temperatures are above freezing and remain in the range of 35°F (1.7°C) to 55°F (12.8°C) with rare extreme weather except for occasional snowstorms at high altitudes. Weather in February »

Weather in March

March is cold in Oregon as the state tries to free itself from the clutches of the winter. The icy roads thaw steadily under the influence of the warm sunshine. The average temperatures across the state range from a freezing 19°F (-7.2°C) in the Cascades to a warm 57°F (13.9°C) along the coastal regions. Weather in March »

Weather in April

April welcomes the beautiful spring season to Oregon with its mild weather that spreads a blanket of greenery over the landscape. The average high temperatures range from 53°F (11.7°C) to 62°F (16.7°C), while the low temperatures average between 23°F (-5°C) to 43°F (6.1°C). Weather in April »

Weather in May

May is a warm spring month with many sunny days amid bright skies in Oregon. The average high temperatures in the state are in the pleasant 49°F (9.4°C) to 75°F (23.9°C) range, while the average low temperatures are in the mild 28°F (-2.2°C) to 46°F (7.8°C). Weather in May »

Weather in June

June is the beginning of the summer in Oregon that sees a significant rise in heat and humidity. Day temperatures are in the range of 58°F (14.4°C) to 84°F (28.9°C), while nights record between 33°F (0.6°C) to 52°F (11.1°C) across the state. Weather in June »

Weather in July

July is usually the hottest and sunniest month of the year in Oregon. The average high temperatures across the state are between 64°F (17.8°C) to 94°F (34.4°C) with many cities in the range of 85°F (29.4°C) to 90°F (32.2°C). Weather in July »

Weather in August

August is a hot summer month in Oregon with sunny days and clear skies. The arid lands in the central and eastern parts experience vast temperature differences of 35°F (1.7°C) to 40°F (4.4°C) between day and night. Willamette Valley has mild temperatures that often remain below 80°F (26.7°C). Weather in August »

Weather in September

September has comfortable conditions in Oregon with the arrival of the fall season. The weather is pleasant, and light breezes make the evenings enjoyable near the coast. The autumn wears a colorful cloak, which grows in beauty by the third week of September. The temperatures are moderate, with the majority of the state registering average high temperatures below 85°F (29.4°C). Weather in September »

Weather in October

October is the time for peak fall foliage in Oregon as the state braces for a drop in night temperatures. The average high temperatures are comfortably warm in the 55°F (12.8°C) to 70°F (21.1°C) range, but the nights are cold with the average low temperatures in the 32°F (0°C) to 48°F (8.9°C) range. The coastal areas offer gorgeous warm days at the beach, but the Cascades may see the first flurry of snow. Weather in October »

Weather in November

November ends the beautiful fall season in Oregon to push it into the arms of winter. Day temperatures are in the average range of 46°F (7.8°C) to 57°F (13.9°C), but the nights are below freezing in many places as they register in the 27°F (-2.8°C) to 45°F (7.2°C) zone. Weather in November »

Weather in December

December brings the cold winter to Oregon with the average high temperatures in the 35°F (1.7°C) to 55°F (12.8°C) range and the average low temperatures in the chilly 11°F (-11.7°C) to 42°F (5.6°C) range across the state. Weather in December »


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