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January Weather in Forest Grove, United States

Last updated: June 24, 2025

In January, the average temperature in Forest Grove, United States hovers around 5°C (42°F). You can expect temperatures to fluctuate between a chilly -12°C (10°F) and a milder 14°C (58°F). During this time, precipitation is notable, with around 173 mm (6.8 in) falling over 17 days, contributing to an average humidity of 85%.

January Temperature in Forest Grove

In January in Forest Grove, the average temperature is 5°C (42°F), with maximums reaching 14°C (58°F) and minimums dropping as low as -12°C (10°F). Be prepared for chilly weather and pack accordingly when traveling during this time.

January Weather in Forest Grove: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Forest Grove, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Forest Grove, January typically has an average temperature of 5°C (42°F), with highs reaching up to 14°C (58°F) and lows dropping to around -12°C (10°F).
JanFebMarAprMayJunJulAugSepOctNovDec414145515763687063534641
Data source: Temperature data for Forest Grove generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

January Precipitation in Forest Grove

In Forest Grove in January, the precipitation amount is 173 mm (6.8 in) spread over 17 days.

January Precipitation Trends in Forest Grove

The chart displays monthly precipitation patterns in Forest Grove, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Forest Grove, January typically receives around 173 mm (6.8 inches) of precipitation spread over approximately 17 days.
JanFebMarAprMayJunJulAugSepOctNovDec17316613211555476666101163188
Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.
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January Humidity in Forest Grove

In Forest Grove in January, humidity is 85%. With an average temperature of 5°C (42°F), this humidity feels like a damp chill that clings to your skin, making outdoor activities uncomfortable and requiring extra layers to stay warm while exploring.

January Average Humidity in Forest Grove

This chart illustrates the average monthly humidity levels in Forest Grove, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Forest Grove is approximately 85%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%84%85%83%83%84%82%74%71%81%87%87%
Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Forest Grove

In Forest Grove in January, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Forest Grove, you can visit Hourly UV Index in Forest Grove.

Maximum UV Index Levels in Forest Grove for January

The chart shows the monthly maximum UV Index (UVI) for Forest Grove in January, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In January, the maximum UV index in Forest Grove typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec23579101087532
Data source: Forest Grove January UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How January Weather in Forest Grove Compares to Other Months

Weather in Forest Grove varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Forest Grove, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Forest Grove, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather5°C (42°F)173 mm (6.8 inches)85%low
February Weather5°C (41°F)166 mm (6.5 inches)84%moderate
March Weather7°C (46°F)132 mm (5.2 inches)85%moderate
April Weather10°C (51°F)115 mm (4.5 inches)83%high
May Weather14°C (58°F)55 mm (2.2 inches)83%very high
June Weather17°C (64°F)47 mm (1.9 inches)83%very high
July Weather20°C (69°F)5 mm (0.2 inches)82%very high
August Weather21°C (70°F)6 mm (0.2 inches)74%very high
September Weather17°C (64°F)66 mm (2.6 inches)71%high
October Weather11°C (53°F)101 mm (4.0 inches)81%moderate
November Weather8°C (46°F)163 mm (6.4 inches)87%moderate
December Weather5°C (41°F)188 mm (7.4 inches)87%low

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