January Weather in Napa, United States

Last updated: February 24, 2025

January in Napa, United States, offers a dynamic blend of winter weather, characterized by a maximum temperature of 25°C (77°F) and an average chill of 10°C (50°F). Nighttime temperatures can drop as low as -2°C (29°F), showcasing the region's crisp winter nights. With a total precipitation of 119 mm (4.7 in) spread over 8 rainy days, January can be quite wet, contributing to a high humidity level of 84% that envelops the area. This combination of temperatures and weather conditions creates a unique atmosphere in Napa, perfect for both cozy indoor experiences and refreshing outdoor explorations.

January Temperature in Napa

In January, Napa experiences a refreshing chill, with temperatures ranging from a brisk -2°C (29°F) at night to a pleasant 25°C (77°F) during the day. This month sets the stage for a gradual warming trend, as seen in February when the minimum temp rises slightly to -1°C (30°F) and daytime highs push closer to 27°C (80°F). As spring approaches, temperatures continue to climb, reaching an inviting 12°C (55°F) average by March, with highs soaring to 30°C (87°F). The transition from winter to spring becomes increasingly evident, paving the way for warmer months ahead. This warming pattern culminates in the summer months, where temperatures can soar above 40°C (104°F), showcasing Napa's distinct seasonal shift that keeps its climate both diverse and dynamic.

January Weather in Napa: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Napa, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec505254596470707070655550
Data source: Temperature data for Napa generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

January Precipitation in Napa

January marks a notable start to the year in Napa, United States, with an average precipitation of 119 mm (4.7 in), making it the wettest month of the year. Rainfall typically graces the region on about 8 days, ensuring the landscape remains lush and vibrant. Interestingly, precipitation begins to taper off in February with 113 mm (4.5 in), followed by a significant drop in March to 81 mm (3.2 in), indicating a swift transition to drier conditions. As spring approaches, April sees rainfall plummet to 33 mm (1.3 in), and by May, it dwindles to just 19 mm (0.8 in), heralding the onset of Napa's typically dry summer months. This trend starkly contrasts with the abundant moisture of winter, emphasizing the region's seasonal variability and setting the stage for the sun-kissed days ahead.

January Precipitation Trends in Napa

The chart displays monthly precipitation patterns in Napa, 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.
JanFebMarAprMayJunJulAugSepOctNovDec1201138133192001294391
Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.
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January Humidity in Napa

In Napa, the weather is characterized by high humidity at the start of the year, with January and February each recording a moisture-laden 84%. As the seasons progress, there’s a gradual decline in humidity, dropping to 81% by April and further down to 74% in May. This reduction continues into the summer months, with July and August experiencing significantly lower levels at 44% and 36%, respectively. However, as autumn approaches, the humidity begins to climb again, peaking at 84% in November before slightly tapering off in December. This trend highlights the seasonal ebb and flow of humidity in Napa, making the winter months distinctly moist and the summer months notably dry.

January Average Humidity in Napa

This chart illustrates the average monthly humidity levels in Napa, with January's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how January's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec84%84%83%81%74%64%44%37%44%65%84%83%
Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Napa

In Napa, January welcomes moderate UV exposure with an index of 3, allowing for a relatively safe burn time of 30 minutes. This trend of careful sun exposure continues into February, with a slight increase to a UV Index of 5, but the warning remains that skin protection is wise. As spring approaches in March, the UV Index climbs to 7, signaling a shift towards higher sun intensity and a reduced 25-minute burn time. The trajectory doesn't stop there—April and May bring even more striking increases, with indices reaching 9 and 10 respectively, enforcing a critical need for sun safety. By summer, UV levels peak at 11 in both June and July, resulting in an alarming burn time of just 10 minutes. If you’re planning outdoor activities during these months, understanding the trends and adjusting your sun protection is paramount. As summer gives way to autumn, there’s a gradual decline in UV levels, but even in November, the index remains at 4, reminding everyone to stay vigilant. For detailed insights into UV trends year-round, check out Napa UV Index.

Maximum UV Index Levels in Napa for January

The chart shows the monthly maximum UV Index (UVI) for Napa 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.
JanFebMarAprMayJunJulAugSepOctNovDec3579101111109643
Data source: Napa 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.

January Sunshine in Napa

In Napa, January greets visitors with 141 hours of sunshine, a gentle prelude to a year filled with radiant days. As winter wanes into February, the hours increase significantly to 210, hinting at the vibrant spring ahead. March experiences a further uplift with 257 hours, ushering in the warm embrace of longer days. With each passing month, the sun continues to shine brighter, peaking in July with an impressive 394 hours. The summer months not only delight with long, sun-drenched afternoons but also set the stage for the enchanting harvest season. As autumn arrives, the sunshine gradually recedes, with October basking in 280 hours followed by a gentle decline towards the year's end. This rhythmic dance of sunlight throughout the year showcases Napa's unique allure, making it a coveted destination for sun-seekers and vineyard lovers alike.

Monthly Sunshine Duration in Napa: January Highlighted

The January sunshine duration represents the total number of hours Napa experiences direct sunlight during the month of January, excluding cloudy or obstructed periods. This chart compares the sunshine duration of January with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec141h210h257h296h357h384h394h356h314h280h220h185h
Data source: Napa January Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Napa During January

In Napa, the likelihood of enjoying sunny weather in January is relatively modest at 38%, reflecting the tail end of the wetter winter months. As the year progresses, there's a noticeable upward trend in sunshine, with February jumping to 58% and March further increasing to 63%. By April, the chances rise significantly to 70%, heralding the start of a season filled with vibrant sunshine. This trend continues into the peak summer months, where both May and June boast an impressive 82% likelihood of clear skies. As fall approaches, sunshine remains abundant, although the percentages dip slightly in October and November, ending the year at 31% for December. Overall, Napa transitions from a relatively overcast January to delightfully sunny days as it moves into spring and summer, making it an appealing destination for sun-seekers in the warmer months.

Percentage of Sunny Days in January in Napa

The chart illustrates the percentage of sunny days in Napa throughout the year, with January highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Napa experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec38%58%63%70%82%82%73%79%76%53%45%31%
Data source: Napa January chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Napa in January

In Napa, the transformation of daylight throughout the year is a captivating rhythm that reflects the changing seasons. January begins with just 9 hours of daylight, setting a tranquil stage for winter’s embrace. As February arrives, the days lengthen to 10 hours, and by March, the increasing light signals the awakening of spring with 11 hours. A noticeable surge occurs in April and May, where daylight stretches to 13 and 14 hours, respectively, inviting outdoor adventures and vibrant vineyard activities. The summer months maintain this peak at 14 hours in both June and July, creating an ideal setting for exploration and enjoyment. As the year transitions, August gently tapers to 13 hours, leading into the early fall when September offers 12 hours. The daylight begins to wane again in October and November, returning to 11 and 10 hours, before closing the cycle in December with another 9 hours. This cyclical dance of light not only enhances the beauty of Napa but also profoundly influences its agricultural rhythm and lifestyle throughout the year.

Average Daylight Hours in Napa for January

The chart illustrates the variation in daylight duration in Napa throughout the year, with January highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 50m10h 46m11h 59m13h 13m14h 15m14h 46m14h 29m13h 33m12h 22m11h 8m10h 4m9h 32m
Data source: Napa daylight hours, calculated by summing the hours between sunrise and sunset for each day.

January Winds in Napa

In January, Napa experiences a gentle breeze with an average wind speed of 2.0 m/s (5 mph), setting the tone for a tranquil start to the year. As winter transitions into spring, wind speeds gradually rise, reaching 2.4 m/s (5 mph) in February and climbing further to 2.5 m/s (6 mph) by March. This upward trend continues into the warmer months, peaking in May and June with an invigorating average of 3.1 m/s (7 mph) and 3.3 m/s (7 mph), respectively. Interestingly, the winds begin to mellow again as summer gives way to autumn, declining to 2.4 m/s (5 mph) by September and dropping to 1.6 m/s (4 mph) in November. Ultimately, January's calm winds give way to stronger breezes during spring and summer, only to retreat once more as the year draws to a close, resulting in a rhythmic cycle that perfectly embodies Napa's seasonal character.

Average January Wind Speed in Napa

The chart displays monthly wind speed patterns in Napa, with values for each month shown alongside January's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how January's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec2.0 m/s2.42.52.73.13.33.02.72.42.31.62.0
Data source: Napa January wind data, generated using information from the Copernicus Climate Change Service.

How January Weather in Napa Compares to Other Months

The weather in Napa changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of January's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Napa and find detailed weather information for every month.

In January, temperatures typically range from a minimum of -2°C (29°F) to a maximum of 25°C (77°F), with an average of 10°C (50°F). The month experiences around 119 mm (4.7 in) of precipitation over approximately 8 days. In contrast, February sees slightly milder conditions, with temperatures ranging from -1°C (30°F) to a maximum of 27°C (80°F) and an average temperature of 11°C (53°F). Precipitation levels are slightly lower at 113 mm (4.5 in) over 7 days. Both months share a humidity level of 84%, providing a consistent moisture in the air. For more detailed information, you can explore Napa weather in February.

January tends to be cooler than March, with average temperatures ranging from a minimum of -2°C (29°F) to a maximum of 25°C (77°F), while March sees a slight increase with temperatures starting at 1°C (34°F) and rising to 30°C (87°F). Precipitation is higher in January at 119 mm (4.7 in) over 8 days, compared to March, which experiences 81 mm (3.2 in) over 9 days. Humidity levels are relatively consistent, with January at 84% and March slightly lower at 83%. For more detailed insights, check out this link: Napa weather in March.

January and April present a noticeable contrast in weather conditions. January experiences cooler temperatures, with a minimum of -2°C (29°F) and an average of 10°C (50°F), while April warms up significantly, featuring a minimum of 3°C (38°F) and an average of 15°C (60°F). The maximum temperature in January can reach 25°C (77°F), but April can soar to a much warmer 33°C (92°F). Additionally, January sees more precipitation at 119 mm (4.7 in) over 8 days, compared to April's lighter rainfall of 33 mm (1.3 in) over just 5 days. Despite both months experiencing relatively high humidity, January holds a slightly higher level at 84%, compared to April's 81%. For more detailed insights on the weather in April, visit Napa weather in April.

In January, the weather features a much cooler average temperature of 10°C (50°F), with nighttime lows dipping to -2°C (29°F) and occasional highs reaching 25°C (77°F). This month also tends to be wetter, with 119 mm (4.7 in) of precipitation over about 8 days, resulting in a higher humidity level of 84%. In contrast, May brings warmer conditions, with average temperatures rising to 18°C (64°F), nighttime lows at 5°C (41°F), and maximum temperatures soaring to 37°C (99°F). Precipitation is significantly reduced to just 19 mm (0.8 in) over 2 days, and humidity decreases to 74%. For a more detailed look at the delightful weather in May, check out Napa weather in May.

January and June present contrasting weather patterns that highlight the seasonal shifts. January features a chilly climate with temperatures ranging from a minimum of -2°C (29°F) to an average of 10°C (50°F), peaking at 25°C (77°F). Additionally, it experiences considerable precipitation, totaling 119 mm (4.7 in) over 8 days, and maintains high humidity at 84%. In stark contrast, June boasts much warmer temperatures, with a minimum of 10°C (51°F), an average of 21°C (70°F), and highs reaching a scorching 41°C (106°F). Precipitation is virtually non-existent, with only 2 mm (0.1 in) recorded across 0 days, and lower humidity at 64%. This shift from January's wet chill to June's dry heat is a striking feature of the region's climate. For more details on the June weather, check Napa weather in June.

In January, the weather is significantly cooler, with temperatures ranging from a minimum of -2°C (29°F) to a maximum of 25°C (77°F), and an average temperature of 10°C (50°F). The month also sees considerable precipitation, averaging 119 mm (4.7 inches) over about eight days, coupled with high humidity levels of 84%. In contrast, July brings much warmer temperatures, with a minimum of 11°C (53°F), an average of 21°C (70°F), and a peak reaching up to 40°C (104°F). Remarkably, July experiences virtually no precipitation, entirely dry with 0 mm (0.0 inches) and only 44% humidity. For a closer look at July's weather, check out Napa weather in July.

January and August present striking contrasts in weather. In January, temperatures range from a chilly min of -2°C (29°F) to a mild max of 25°C (77°F), with an average of 10°C (50°F). The month is characterized by significant precipitation, averaging 119 mm (4.7 in) over 8 days, and high humidity at 84%. In stark contrast, August experiences a warm minimum of 12°C (53°F) and can reach scorching highs of 42°C (108°F), with an average temperature of 21°C (71°F). Remarkably, this summer month sees no rainfall, with 0 mm recorded and an average humidity of just 36%. For more detailed insights on August weather, visit Napa weather in August.

January and September present contrasting weather patterns. In January, temperatures range from a chilly minimum of -2°C (29°F) to a comfortable maximum of 25°C (77°F), with an average of 10°C (50°F). This month also sees significant precipitation, with 119 mm (4.7 in) falling over 8 days and high humidity at 84%. In contrast, September enjoys a much warmer climate with minimum temperatures at 8°C (46°F) and a striking maximum of 44°C (111°F), averaging 21°C (70°F). Remarkably, this month experiences almost no rain, with just 1 mm (0.0 in) recorded over 0 days and comfortable humidity at 44%. For more detailed information, visit Napa weather in September.

In January, the weather tends to be considerably cooler, with average temperatures ranging from a minimum of -2°C (29°F) to a maximum of 25°C (77°F). The month experiences significant rainfall, totaling 119 mm (4.7 in) over about 8 days, contributing to a high humidity level of 84%. In contrast, October brings milder temperatures, with a minimum of 4°C (40°F) and a maximum reaching as high as 36°C (98°F). This month sees much less precipitation, with only 29 mm (1.1 in) over just 2 days and lower humidity at 65%. For more details, check out Napa weather in October.

January and November exhibit notable differences in weather patterns. January typically sees a minimum temperature of -2°C (29°F) and an average of 10°C (50°F), with highs reaching up to 25°C (77°F). In contrast, November has milder temperatures, with a minimum of 0°C (32°F), an average of 13°C (56°F), and maximums hitting 30°C (86°F). Additionally, January experiences more rainfall, accumulating 119 mm (4.7 in) over eight days, whereas November is drier, with only 43 mm (1.7 in) of precipitation across five days. Interestingly, both months share a consistent humidity level of 84%. For more specifics on November weather, you can explore Napa weather in November.

January and December display quite similar weather patterns, with both months featuring an average temperature of around 10°C (50°F). However, January tends to be slightly cooler, with minimum temperatures dropping to about -2°C (29°F) compared to December's minimum of 0°C (32°F). In terms of precipitation, January sees an increase with 119 mm (4.7 in) over approximately 8 days, while December has lower rainfall at 91 mm (3.6 in) spread over 9 days. Humidity levels are comparable as well, with January at 84% and December at 83%. For a deeper look into December's conditions, you can visit Napa weather in December.

Compare Napa's Climate with Cities Worldwide

Conclusion: What to Expect From January Weather in Napa

In January, Napa experiences a distinctive shift in weather, marked by cooler temperatures and increased precipitation compared to other months. The average temperature hovers around 10°C (50°F), offering a refreshing contrast to the warmer summer days. This month also brings increased humidity, hovering around 84%, which can make the crisp air feel even chillier. With about eight days of rainfall totaling 119 mm (4.7 in), it's a time when the landscape bursts with life, making it a unique season for visitors. For a deeper understanding of Napa's climate throughout the year, check out Napa Climate.