Last updated: February 24, 2025
In Yountville, United States, September showcases a delightful range of temperatures, with maximums reaching a blazing 44°C (112°F) and a comfortable average of 22°C (72°F). Nights bring a refreshing coolness, dipping to a minimum of 7°C (45°F), perfect for outdoor activities. Rainfall is minimal, with just 1 mm (0.0 in) recorded over zero precipitation days, allowing visitors to enjoy the serene landscapes without interruption. The humidity level sits at a pleasant 44%, creating an ideal atmosphere for exploring the charm of Yountville throughout this sun-drenched month.
In September, Yountville experiences a warm transition as summer draws to a close. The minimum temperature nudges up to 7°C (45°F), providing a mild start to the month, while the average temperature climbs to a pleasant 22°C (72°F). With peaks reaching a sweltering 44°C (112°F), it's one of the hottest months in the region, echoing August's intense warmth. This pattern marks a distinct trend, where temperatures gradually diminish as fall approaches, hinting at the cooler days ahead. As vineyards thrive in the late summer sun, September offers both warmth and the promise of a bountiful harvest, creating an idyllic backdrop for outdoor activities and wine tastings.
In September, Yountville experiences a remarkable dry spell, with only 1 mm (0.0 in) of precipitation and no recorded rain days. This trend follows a pattern established in the preceding months, where July and August also reported negligible rainfall, resulting in an extended period of drought-like conditions. As the region transitions into October, a slight uptick in precipitation is expected, with 31 mm (1.2 in) anticipated over just 2 days. This cyclical shift indicates a return to a more typical fall season, hinting at the seasonal variability that characterizes Yountville's climate.
In Yountville, United States, the humidity patterns throughout the year reveal a clear trend of seasonal variation. Beginning with a high of 84% in both January and February, the atmosphere gradually becomes drier as spring unfolds, reaching a comfortable 74% in May. The summer months bring a notable decline, with July and August showcasing the driest conditions at only 44% and 36% respectively. September sees a slight increase, stabilizing back at 44%, indicating a transition into the more humid fall season. As the months progress into October and November, humidity levels rise again, peaking at 84% in November, thus reflecting the cyclical nature of climate in Yountville, where ambient moisture ebbs and flows throughout the year.
In September, Yountville experiences a UV Index of 9, placing it in the very high exposure category, which means you could get sunburned in just 15 minutes. This trend follows the peak summer months of July and August, where the UV Index reached extremes of 11 and 10 respectively. As the season transitions into autumn, the UV Index begins to decline, but it remains significant compared to earlier months like January and February, which had moderates readings of 3 and 5. Thus, while summer may be over, it's essential to remain vigilant about sun exposure in September. For more detailed information, check out the Yountville UV Index.
UV Risk Categories
September in Yountville shines with an impressive 314 hours of sunshine, rounding off a summer that peaked in July with a delightful 394 hours. As the warm days of summer transition into the crispness of autumn, September retains a generous amount of sunlight, only slightly less than the dazzling heights of the summer months. Following this, the sunshine hours begin to taper off in October, dropping to 280 hours, signaling the approaching chill of winter. Overall, the trend reflects a vibrant late summer that gradually gives way to the softer light of fall, inviting both locals and visitors to savor the beautiful landscapes and flavors of the region.
In Yountville, September enjoys a promising 82% chance of sunny weather, continuing the trend of warmth and brightness that peaks during the summer months. As we transition from the sultry days of August—where sunny skies reign at 89%—September maintains a solid share of sunshine, providing an ideal backdrop for harvest festivities and wine tastings. The month sits comfortably between the summer warmth and the cooler, cloudier days of fall, with the likelihood of sun significantly higher than in the upcoming months of October and November, which dip to 53% and 50%, respectively. Thus, September offers an inviting window for outdoor activities under mostly blue skies, making it a delightful time to soak up the last rays of summer.
As summer fades into autumn, September heralds a gentle decline in daylight hours in Yountville, U.S., offering about 12 hours of sunlight each day. This shift marks a transition from the peak brightness of July and August, which each bask in 14 hours of glorious daylight. The gradual decrease reflects the natural rhythm of the seasons, as fall approaches, pulling back from the longer days experienced in mid-summer. Yet, September still holds onto a generous complement of light, allowing residents and visitors to relish the beautiful, sun-drenched days before the daylight whispers down to 11 hours in October. This blend of fading warmth and extended daylight invites an enchanting exploration of the local vineyards and picturesque landscapes, making September a truly delightful time in Yountville.
As September rolls into Yountville, the gentle whispers of the wind carry a refreshing charm, with average speeds settling at 1.9 m/s (4 mph). This slight dip mirrors the summer's soft surrender to fall, following the peak of 2.6 m/s (6 mph) in May. Interestingly, September's wind speed aligns with August's calm, both creating a serene backdrop that hints at the upcoming changes of autumn. The consistency of the lighter winds in these later summer months signals a transition, inviting residents and visitors alike to bask in the tranquil ambiance before the briskness of October sets in. Overall, the pattern showcases a gradual mellowing, as Yountville enjoys these serene breezes amidst the backdrop of vibrant seasonal shifts.
The weather in Yountville changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Yountville and find detailed weather information for every month.
September and January present quite contrasting weather patterns. In September, temperatures can soar with a maximum of 44°C (112°F) and an average of 22°C (72°F), all while enjoying low humidity at 44% and virtually no precipitation. In stark contrast, January experiences much cooler temperatures, with a minimum of -1°C (30°F) and an average of 10°C (50°F). It also sees significant precipitation, totaling 127 mm (5.0 in) over about 8 days, along with higher humidity at 84%. For a closer look at January conditions, check out Yountville weather in January.
In September, weather can be quite warm, with average temperatures around 22°C (72°F) and peaks reaching up to 44°C (112°F). The month is generally dry, with negligible rainfall and low humidity at 44%. In stark contrast, February brings cooler conditions, with average temperatures dropping to 11°C (53°F) and a minimum temperature of -3°C (28°F). This month is characterized by significant rainfall, totaling 120 mm (4.7 in) over about 7 days, accompanied by higher humidity levels at 84%. For a deeper dive into February conditions, you can check Yountville weather in February.
September and March present quite contrasting weather patterns. In September, temperatures range from a cool 7°C (45°F) at night to a scorching 44°C (112°F) during the day, with an average of 22°C (72°F). This month boasts minimal precipitation, with only 1 mm recorded over zero rainy days, and humidity levels are relatively low at 44%. In stark contrast, March features much cooler weather, with temperatures ranging from a chilly 0°C (32°F) at night to a pleasant 30°C (86°F) during the day, averaging around 12°C (54°F). Additionally, March is significantly wetter, receiving 84 mm (3.3 in) of rain spread over 10 days, alongside heightened humidity levels of 83%. For a more detailed look at March conditions, check out Yountville weather in March.
September weather is characterized by warm temperatures, with an average of 22°C (72°F) and a maximum reaching 44°C (112°F), while April sees milder conditions, averaging 16°C (60°F) and peaking at 33°C (92°F). In September, precipitation is virtually absent, with just 1 mm recorded over 0 days, contrasting sharply with April's 32 mm spread over 5 days, showcasing a much wetter climate during that month. Additionally, September enjoys lower humidity at 44%, while April is much more humid at 81%. For more details on the specific conditions in April, you can check Yountville weather in April.
September typically offers warmer weather compared to May, with average temperatures reaching 22°C (72°F) and highs soaring up to 44°C (112°F). In contrast, May presents milder conditions, with an average temperature of 19°C (66°F) and maximums around 38°C (101°F). While September enjoys dry days with little precipitation (only 1 mm), May experiences more humidity at 74% and sees about 20 mm of rainfall over two days. For a closer look at May's weather, check out Yountville weather in May.
In September, temperatures exhibit a broader range with a minimum of 7°C (45°F) and a maximum reaching up to 44°C (112°F), while the average sits comfortably at 22°C (72°F). The month is notably dry, with only 1 mm of precipitation recorded and no rainy days. Humidity is relatively low at 44%.
Contrastingly, June shows slightly higher minimum temperatures at 9°C (49°F) and a similar maximum of 42°C (108°F), maintaining a comparable average of 23°C (74°F). Although precipitation is slightly higher at 2 mm, there are still no rainy days recorded. However, June experiences higher humidity levels at 64%, contributing to a more humid atmosphere than September.
For more detailed insights on the weather, you can check out Yountville weather in June.
In comparing the weather of September and July, we can observe some notable differences. September typically experiences a minimum temperature of 7°C (45°F), while July's minimum is higher at 12°C (54°F). The average temperature in September stands at 22°C (72°F), slightly lower than July's average of 24°C (76°F). Additionally, both months have a maximum temperature of 44°C (112°F) in September and 41°C (106°F) in July, indicating that July is generally a bit cooler. Interestingly, both months report negligible precipitation of just 1 mm (0.0 in) with no rainy days and maintain the same humidity level of 44%. For a more detailed look at July weather, you can check here: Yountville weather in July.
In comparing the weather patterns of September and August, we notice a slight cooling trend, with September exhibiting a minimum temperature of 7°C (45°F) compared to August's 11°C (52°F). The average temperatures are also lower in September at 22°C (72°F), whereas August sees a warmer average of 24°C (75°F). Although both months experience minimal precipitation, September records only 1 mm over zero days, while August has no recorded precipitation at all. Notably, September's humidity is higher at 44% compared to August's 36%, contributing to a different overall feel. For more detailed insights on August weather, you can check out Yountville weather in August.
In September, the weather features mild temperatures, with a minimum of 7°C (45°F), an average of 22°C (72°F), and a maximum reaching a scorching 44°C (112°F). The month is characterized by negligible precipitation, with only 1 mm recorded and no rainy days, along with a relatively low humidity of 44%. In contrast, October brings a noticeable shift, with lower temperatures averaging around 19°C (66°F), starting at a minimum of 4°C (39°F) and peaking at 38°C (101°F). This month sees a significant increase in precipitation, totaling 31 mm (1.2 in) over two days, and the humidity rises to 65%. For more detailed information, check out Yountville weather in October.
September and November present stark contrasts in weather conditions. In September, temperatures range significantly, with a minimum of 7°C (45°F) and an average high of 22°C (72°F), peaking at a sweltering 44°C (112°F). Rainfall is virtually nonexistent, with only 1 mm recorded over no rainy days and humidity levels at a moderate 44%. In comparison, November brings cooler temperatures, with a minimum of -1°C (30°F) and an average of 13°C (56°F), and highs reaching 29°C (85°F). Precipitation increases dramatically to 43 mm spread over five days, contributing to a higher humidity level of 84%. This change in climate reflects the transition from the warm, dry days of late summer to the cooler, wetter conditions typical of late fall. For more details on November's weather, visit Yountville weather in November.
September and December present contrasting weather patterns. In September, temperatures range from a refreshing minimum of 7°C (45°F) to a scorching maximum of 44°C (112°F), with an average of 22°C (72°F). The month boasts very low precipitation, with only 1 mm recorded over 0 days and a humidity level of 44%. In stark contrast, December features much cooler temperatures, with a minimum of 0°C (33°F) and an average of 10°C (50°F), peaking at 23°C (75°F). Additionally, December experiences significantly higher precipitation, totaling 87 mm (3.4 in) over 8 days, alongside a marked increase in humidity at 83%. For more detailed insights on December weather, you can visit Yountville weather in December.
As the summer heat begins to fade, September in Yountville offers a delightful transition to milder temperatures and lower humidity, making it one of the most pleasant months of the year. With days that soar to a maximum of 44°C (112°F), yet cool off significantly at night, this month provides an ideal blend for outdoor activities. Unlike the wetter months that follow, September boasts zero precipitation days and a mere 1 mm of rain, ensuring clear skies and abundant sunshine. As the air remains refreshingly dry with 44% humidity, visitors can fully enjoy the scenic beauty and vibrant atmosphere. To learn more about what to expect throughout the year, visit Yountville Climate.