Climate and monthly weather forecast
Forest Grove, OR

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The climate of Forest Grove

Forest Grove, Oregon, falls under the Köppen climate classification of Csb. This classification translates to a Mediterranean climate with warm summers and an overall temperature range between 33.1°F (0.6°C) in the colder months to 79.3°F (26.3°C) in the height of summer. Forest Grove experiences a substantial amount of precipitation throughout the year with a comparatively mild amount of snowfall, measuring a mere 1.54" (39mm) in February and negligibly less in January and December.

The climate variables show significant fluctuations across the year. Several weather elements stand out — the wind, precipitation, sunlight, and temperature. Wind speeds tend to remain relatively constant throughout the year, ranging from 4mph (6.4km/h) to 4.9mph (7.9km/h). However, gusts can reach up to 8.1mph (13km/h) during November. Precipitation is another noticeable element, with rainfall peaking to 5.47" (139mm) in January and reducing to a minimum of 0.47" (12mm) in July and August.

Sunlight hours also display a remarkable shift from around 15 hours in summer, gradually reducing to approximately 9 hours during winter months. Throughout the year, the temperature also illustrates considerable variation with high temperatures peaking at 79.3°F (26.3°C) during August, whereas the coldest temperature dips to 33.1°F (0.6°C) during December.

The best time to visit Forest Grove

According to the climatological data, the best time to visit Forest Grove would be from late spring to early fall, specifically between May and September. During this period, the city experiences its warmest temperatures, around 65.3°F (18.5°C) to 79.3°F (26.3°C), and the least amount of rainfall, approximately 0.47" (12mm) in July and August. Combined with the city's longest daylight hours, visitors can enjoy various outdoor activities under pleasant weather conditions.

The worst time to visit Forest Grove

By examining the climatological parameters, the least favorable time to visit Forest Grove tends to be from late fall to early spring, particularly between November and March. This period experiences lowered temperatures, ranging from 43°F (6.1°C) to 46.4°F (8°C), along with increased precipitation levels, reaching a maximum of 5.39" (137mm) in December. Additionally, these months offer the least amount of sunlight and the highest relative humidity, leading to potentially uncomfortable conditions for visitors.

Spring weather in Forest Grove

Spring in Forest Grove is characterized by moderately warm and rainy conditions. Temperatures during this season steadily increase, starting from 46.4°F (8°C) in March and rising to 56.5°F (13.6°C) by May. Correspondingly, precipitation values decrease, with rainfall diminishing from 3.9" (99mm) in March to 2.09" (53mm) in May. The daylight hours also exhibit a rise, extending from 12 hours in March to around 15 hours by May, perfect for indulging in outdoor excursions.

Summer weather in Forest Grove

Summer in Forest Grove displays characteristics of a Mediterranean climate — warm and dry weather conditions dominate this period. The average high temperature ranges from 70.2°F (21.2°C) in June to 79.3°F (26.3°C) in August. In line with this, rainfall amounts significantly reduce to mere 0.47" (12mm) in July and August, and the city basks in the maximum daylight hours, approximately 15 hours per day, during these months.

Autumn weather in Forest Grove

In autumn, Forest Grove witnesses gradual temperature decrease and an increase in precipitation. Average high temperatures fall from 71.6°F (22°C) in September to 49.3°F (9.6°C) by November, while the rainfall quantity steadily escalates from 1.57" (40mm) in September to 3.74" (95mm) in November. The amount of daily sunlight also drops during this season, reducing from approximately 13 hours in September to 9 hours by November.

Winter weather in Forest Grove

Winter months in Forest Grove, Oregon, are chilly and rainy. From December to February, the average high temperatures hover around 43°F (6.1°C) to 46.4°F (8°C) while low temperatures dip down to 33.1°F (0.6°C) in December. Corresponding to this, the precipitation reaches its yearly high values, measuring 5.47" (139mm) in January. Furthermore, the city witnesses the shortest daylight hours, lessening to 8.8 hours during December, the darkest month of the year.

Weather in January

January marks the beginning of the year in Forest Grove, Oregon, with the weather displaying typical winter characteristics. Notably, the temperatures range from a high of 44.4°F (6.9°C) to a low of 33.6°F (0.9°C) this month. Weather in January »

Weather in February

As Winter advances in Forest Grove, February offers slightly warmer temperatures than January. The monthly maximums register at 46.4°F (8°C) with the minimums at 34.3°F (1.3°C), marking a mild increase from the previous month. Weather in February »

Weather in March

In Forest Grove, March opens the door to Spring, bringing a shift in weather patterns. The temperatures start to climb with highs reaching 50.5°F (10.3°C) and lows at 36.1°F (2.3°C). This month also boasts increased daylight hours, a welcome change for locals. Weather in March »

Weather in April

April in Forest Grove, Oregon begins to hint at the upcoming Summer season. During this month, the temperature reaches a high of 56.5°F (13.6°C) while dropping to a low of 37.9°F (3.3°C). The city starts to dry up in April, experiencing a significant decrease in rainfall. Weather in April »

Weather in May

In May, Forest Grove, Oregon, truly embraces the Summer weather. This month, the temperature scales up to an average high of 65.3°F (18.5°C) and the average low stands at 43°F (6.1°C). This also ushers in longer daylight hours, adding an element of warmth to the entire city. Weather in May »

Weather in June

June in Forest Grove exhibits quintessential Summer weather. With temperatures scaling between a high of 70.2°F (21.2°C) and a low of 46.8°F (8.2°C), locals venture outdoors more often. June shares May's clear weather while introducing slightly warmer temperatures. Weather in June »

Weather in July

July is a hot month in Forest Grove, with the temperature peaking at a scorching 77.5°F (25.3°C) and a minimum of 51.4°F (10.8°C). The humidity starts to fall, bringing some respite from the Summer heat. The panorama of the city morphs into a Summer haven; tourists flock in to enjoy the sun-soaked climate. Weather in July »

Weather in August

August is the peak of Summer in Forest Grove, with temperatures reaching an impressive high of 79.3°F (26.3°C) while the lows hover around 53.2°F (11.8°C). August promises seemingly endless days filled with bright sunshine and blue skies. Weather in August »

Weather in September

Forest Grove welcomes the Autumn season in September, bundling up to combat the dropping temperatures. September also brings increased rainfall, signaling a transition from the dry Summer months. Despite the mild coolness, the temperatures this month are still relatively high, hovering around a maximum of 71.6°F (22°C) and a minimum of 49.8°F (9.9°C). Weather in September »

Weather in October

October in Forest Grove, Oregon showcases a further drop in temperature documenting highs at 59.5°F (15.3°C) and lows at 43.9°F (6.6°C). The first signs of early winter become palpable; shorter days and longer nights become the norm. Weather in October »

Weather in November

November in Forest Grove, Oregon rings in Winter with all its might. The month sees temperatures plunging to a chilly 38.5°F (3.6°C) at their lowest; the highest temperature clocks in at a tenable 49.3°F (9.6°C). Rainfall is noticeably prominent in November, often leading to misty mornings and overcast days. Weather in November »

Weather in December

December rounds off the year in Forest Grove, with the city caught in the full swing of winter. Temperatures between 43°F (6.1°C) and 33.1°F (0.6°C) can be expected this month. The chances of snowfall increase marginally, making December one of the colder months. Weather in December »
Updated: Aug 29, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the wettest month?

The month with the most rainfall is January, when the rain falls for 19.3 days and typically aggregates up to 5.47" (139mm) of precipitation.

How much does it rain?

In Forest Grove, during the entire year, the rain falls for 183.5 days and collects up to 34.45" (875mm) of precipitation.

When does it snow in Forest Grove?

Months with snowfall in Forest Grove are January through March, November and December.

How much does it snow?

In Forest Grove, during the entire year, snow falls for 7.1 days and aggregates up to 4.69" (119mm) of snow.

What is the month with the least sunshine?

January and February, with an average of 3.5h of sunshine, are months with the least sunshine in Forest Grove.

What is the most humid month?

February and December, with an average relative humidity of 88%, are most humid months.

When does it snow the most?

February is the month with the most snowfall. Snow falls for 2.9 days and accumulates 1.54" (39mm) of snow.

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?

June has the longest days of the year, with an average of 15h and 36min of daylight.

When is the highest UV index in Forest Grove?

June and July, with an average maximum UV index of 5, are months with the highest UV index in Forest Grove.

What is the driest month?

July and August are months with the least rain when the rain falls for 6.5 days and typically aggregates up to 0.47" (12mm) of rain.

What part of the year is the hottest?

Forest Grove's temperatures peak on average in August, reaching 79.3°F (26.3°C) at their highest and 53.2°F (11.8°C) at their lowest.

What is the least humid month?

August is the least humid month, with an average relative humidity of 69%.

What month has the most sunshine?

The month with the most sunshine is August, with an average of 10.4h of sunshine.

What is the month with the lowest UV index?

The month with the lowest UV index is November, with an average maximum UV index of 1.

What time of the year is the coldest?

With average high and low temperatures of 43°F (6.1°C) and 33.1°F (0.6°C) respectively, December is Forest Grove's coldest month.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 8h and 48min of daylight.

Average temperature
Forest Grove, OR

Average temperature - Forest Grove, OR

The warmest month (with the highest average high temperature) is August (79.3°F).
The month with the lowest average high temperature is December (43°F).

The month with the highest average low temperature is August (53.2°F).
The coldest month (with the lowest average low temperature) is December (33.1°F).

Average pressure
Forest Grove, OR

Average pressure - Forest Grove, OR

The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).

Average wind speed
Forest Grove, OR

Average wind speed - Forest Grove, OR

The windiest month (with the highest average wind speed) is March (4.9mph).
The calmest month (with the lowest average wind speed) is August (4mph).

Average humidity
Forest Grove, OR

Average humidity - Forest Grove, OR

The months with the highest relative humidity are February and December (88%).
The month with the lowest relative humidity is August (69%).

Average rainfall
Forest Grove, OR

Average rainfall - Forest Grove, OR

The wettest month (with the highest rainfall) is January (5.47").
The driest months (with the least rainfall) are July and August (0.47").

Average rainfall days
Forest Grove, OR

Average rainfall days - Forest Grove, OR

The month with the highest number of rainy days is March (21.4 days).
The month with the least rainy days is August (6.2 days).

Average snowfall
Forest Grove, OR

Average snowfall - Forest Grove, OR

The month with the highest snowfall is February (1.54").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days
Forest Grove, OR

Average snowfall days - Forest Grove, OR

The month with the highest number of snowfall days is February (2.9 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average daylight / Average sunshine
Forest Grove, OR

Average daylight / Average sunshine - Forest Grove, OR

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).

The month with the most sunshine is August (Average sunshine: 10h and 24min).
The months with the least sunshine are January and February (Average sunshine: 3h and 30min).

Average sunshine days
Forest Grove, OR

Average sunshine days - Forest Grove, OR

The month with the most sunshine days is August (22 days).
The month with the least sunshine days is March (7.6 days).

Average visibility
Forest Grove, OR

Average visibility - Forest Grove, OR

The months with the highest visibility are July and August (6mi).
The months with the lowest visibility are January, February, March, November and December (4mi).

Forest Grove, Oregon, USA

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