Last updated: February 24, 2025
In September, Walla Walla experiences a dynamic climate marked by a maximum temperature soaring to 36°C (97°F), while the average settles at a comfortable 17°C (62°F). Nights can be quite crisp, with lows dipping to 1°C (35°F). Though the month grants a delightful end to summer, it brings a total precipitation of 25 mm (1.0 in) over just 4 days, maintaining a moderate humidity level of 58%. This blend of warm days and cooler nights enhances Walla Walla's allure, making it a vibrant time for outdoor activities and exploration.
In September, Walla Walla, United States, transitions into the early whispers of fall, with temperatures reflecting a delightful blend of summer's warmth and autumn's chill. The minimum temperature dips to a cool 1°C (35°F), while the average reaches a comfortable 17°C (62°F), perfect for outdoor activities. Daytime highs can soar to an impressive 36°C (97°F), showcasing the month’s lingering summer vibes. This fluctuation creates a unique atmosphere where sunny afternoons invite adventures, yet the crisp evenings hint at the upcoming seasonal shift. As summer gradually yields to fall, September serves as a beautiful bridge, making it an ideal time to explore the region's vineyards and scenic landscapes before winter sets in.
In September, Walla Walla experiences a modest shift in precipitation patterns, with 25 mm (1.0 in) of rain typically falling over four days. This marks a noticeable increase from the dry summer months, particularly July's near-desert conditions, where no rain was recorded. As the city transitions into autumn, the precipitation begins to pick up—setting the stage for a wetter October ahead, which averages 62 mm (2.4 in) over roughly 10 days. The gradual rise in rainfall serves as a reminder of the changing seasons, bringing relief to the lingering summer heat and nourishing the landscape before the onset of winter's more substantial downpours.
In Walla Walla, September marks a notable shift in humidity levels, with a drop to 58%, making it the driest month of the year. This decrease follows the summer months, where humidity levels have already begun to wane, peaking at 60% in August. As the year progresses from January's high of 86%, we observe a consistent decline through the spring and summer, culminating in September's refreshing lower humidity. However, as autumn sets in, humidity levels gradually rise again, reaching 75% by October. This pattern highlights Walla Walla's transition from the humid embrace of winter to the more arid conditions of late summer and early fall.
As September rolls into Walla Walla, the UV Index reflects a high exposure category at 7, signaling a shift from the intense summer months. While the burn time extends back to 25 minutes, this is still a reminder to protect your skin as the sun begins to mellow. Interestingly, the UV Index decreases from its peak of 10 in July and June, where minimal exposure was critical at just 15 minutes to avoid burns. This trend suggests a gradual easing of intense sunlight, perfect for enjoying the outdoors with a bit more safety. For a detailed month-by-month breakdown of the UV Index, visit Walla Walla UV Index.
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As the vibrant hues of autumn begin to paint Walla Walla, September shines as a transitional month, boasting 292 hours of sunlight. This charming increase follows the peak of summer, where the longest days of July yield 411 hours. By September, the daylight begins to retreat but still offers ample sunshine, making it a delightful time for outdoor activities and vineyard visits. The gradual decline in hours from August's 356 to September's 292 reflects a smooth transition into fall, with shorter days yet a warm, golden light that illuminates the landscape, allowing residents and visitors to savor the lingering warmth before winter sets in.
As summer wanes, September in Walla Walla enjoys a robust 65% chance of sunny weather, reflecting a pleasant continuation of the sunny season. This marks a slight decline from the peak of 83% in July, but remains higher than the average for the earlier months of the year, such as 23% in January and 27% in February. Compared to June's 69% and August's 70%, September still holds its own, providing residents and visitors alike with ample opportunities for outdoor activities amidst the vibrant autumn foliage. The trend reveals a gradual transition towards more overcast conditions as the year progresses, yet September stands out as a delightful bridge between summer's warmth and autumn's charm.
In Walla Walla, September marks a gentle transition from the long, sun-soaked days of summer to the shorter daylight hours of fall. With 12 hours of daylight, September offers a balanced blend of light, allowing residents to savor the lingering warmth while beginning to embrace the crispness of autumn. This month sees a noticeable decrease from the peak summer months of June and July, where daylight stretches to a generous 15 hours, yet still retains more sun than the upcoming October, which will further dip to 10 hours. As the days grow shorter, the change signals nature's shift, inviting residents to enjoy the last moments of warm evenings and vibrant sunsets before the charm of winter begins.
In September, Walla Walla experiences a gentle decline in average wind speed, settling at 2.4 m/s (5 mph), the lowest point of the year. This shift marks a transition from the summer's calm breezes, where speeds lingered around 2.5 to 2.7 m/s, to a more serene backdrop as autumn approaches. Notably, September's winds are noticeably less aggressive compared to the earlier months of the year, particularly when contrasted with the slightly brisker conditions of November. As the season changes, the soothing winds of September invite residents and visitors alike to enjoy the beautiful landscapes of Walla Walla, reminding us that nature's rhythm is both gradual and captivating.
The weather in Walla Walla 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 Walla Walla and find detailed weather information for every month.
September and January present stark contrasts in weather conditions. In September, temperatures range from a cool 1°C (35°F) at night to a hot 36°C (97°F) during the day, with an average of 17°C (62°F). The month sees relatively low precipitation, with only 25 mm (1.0 in) falling over 4 days and a moderate humidity level of 58%. In contrast, January experiences much colder temperatures, with a minimum of -19°C (-1°F) and a maximum of just 12°C (54°F), leading to an average of 1°C (34°F). Additionally, January is significantly wetter, accumulating 77 mm (3.0 in) of precipitation over 13 days, accompanied by higher humidity at 86%. For a closer look at January weather specifics, visit Walla Walla weather in January.
September and February present starkly contrasting weather conditions. In September, temperatures range from a low of 1°C (35°F) to a high of 36°C (97°F), with an average of 17°C (62°F) and only 25 mm (1.0 in) of precipitation over about 4 days. The humidity level is moderate at 58%. In contrast, February experiences much colder temperatures, with a minimum of -17°C (2°F), an average of 1°C (34°F), and a maximum of 16°C (61°F). This month sees significantly higher precipitation at 125 mm (4.9 in) spread across 18 days, accompanied by higher humidity at 86%. For more detailed information, you can check Walla Walla weather in February.
Comparing the weather in September and March reveals notable differences in both temperature and precipitation patterns. September boasts a mild average temperature of 17°C (62°F), with highs reaching up to 36°C (97°F), making it generally warmer and drier, experiencing only 25 mm (1.0 in) of precipitation over just four days. In contrast, March presents a much cooler climate with an average temperature of 5°C (41°F), featuring lows as low as -12°C (11°F), and maximum temperatures only reaching 18°C (65°F). It also sees significantly more precipitation at 75 mm (3.0 in) across 13 days, coupled with higher humidity at 85%. For more detailed insights, check out Walla Walla weather in March.
When comparing the weather in September and April, a striking contrast emerges. September boasts warmer average temperatures, ranging from a comfortable 17°C (62°F) to a high of 36°C (97°F), while April's temperatures are much cooler, with averages around 9°C (48°F) and a maximum of 27°C (80°F). Additionally, September is relatively drier, receiving only 25 mm (1.0 in) of precipitation over about 4 days, whereas April experiences more rainfall, totaling 62 mm (2.4 in) across approximately 11 days. April also tends to be more humid, with levels reaching 83%, compared to September's 58%. For more detailed information, you can check Walla Walla weather in April.
September generally offers warmer temperatures compared to May, with an average of 17°C (62°F) and a maximum that can soar up to 36°C (97°F). In contrast, May has a cooler average of 14°C (57°F) and a maximum of 32°C (90°F). While September experiences relatively low precipitation at 25 mm (1.0 in) over about 4 days, May sees nearly double the rainfall at 48 mm (1.9 in) across 9 days, contributing to its higher humidity levels of 77% compared to September's 58%. For more detailed information, check out Walla Walla weather in May.
When comparing the weather in September and June, there are notable differences in temperature and humidity. September experiences a wider temperature range, with a minimum of 1°C (35°F) and a maximum of 36°C (97°F), giving an average temperature of 17°C (62°F), while June has a higher minimum of 4°C (39°F) and can reach up to 43°C (110°F) with an average of 18°C (65°F). Additionally, June tends to be more humid, with a humidity level of 81%, compared to September's 58%. Precipitation levels are relatively similar, with September receiving 25 mm (1.0 in) over 4 days and June slightly more at 27 mm (1.1 in) over 6 days. For more detailed insights, you can check Walla Walla weather in June.
In comparing the weather of September and July, it's evident that both months experience significant temperature variations. September starts with a minimum temperature of 1°C (35°F) and averages 17°C (62°F), peaking at a warm 36°C (97°F), while July has a milder minimum of 7°C (45°F) and a higher average of 23°C (74°F), reaching a maximum of 39°C (103°F). Precipitation differs markedly as well, with September experiencing 25 mm (1.0 in) of rain over 4 days, compared to July's remarkably dry conditions with only 2 mm (0.1 in) of rain and no rainy days at all. Additionally, July has higher humidity levels at 76%, compared to September's 58%. For more detailed insights, you can visit Walla Walla weather in July.
In comparing the weather between August and September, we see notable differences in temperature and precipitation patterns. September experiences cooler minimum temperatures, dropping to 1°C (35°F) compared to August's 6°C (42°F), while the average temperature decreases from 22°C (72°F) in August to 17°C (62°F) in September. However, September can still reach a high of 36°C (97°F), just slightly lower than August's maximum of 39°C (102°F). Precipitation in September is higher at 25 mm (1.0 in) over 4 days, whereas August sees only 8 mm (0.3 in) across just 1 day, indicating a shift toward wetter conditions as summer transitions into fall. Humidity is fairly consistent, with September at 58% and August slightly higher at 60%. For more detailed insights into the August weather, Walla Walla weather in August provides a comprehensive overview.
The weather in September typically presents a wider temperature range, with minimums around 1°C (35°F) and maximums peaking at 36°C (97°F), while averaging a comfortable 17°C (62°F). In contrast, October sees cooler temperatures, with minimums dropping to -11°C (13°F) and an average of 9°C (49°F), though it can still reach up to 28°C (83°F) on warmer days. Additionally, October is characterized by increased precipitation at 62 mm (2.4 in) over 10 days, compared to September's 25 mm (1.0 in) spread over just 4 days; this leads to a noticeable rise in humidity from September's 58% to October's 75%. For more detailed information, check out Walla Walla weather in October.
In comparing the weather between September and November, it’s clear that significant changes occur. September experiences a wide temperature range, with a minimum of 1°C (35°F) and a scorching maximum of 36°C (97°F), leading to an average of 17°C (62°F). The month is relatively dry with only 25 mm (1.0 in) of precipitation over 4 days and a humidity level of 58%. In stark contrast, November sees much cooler temperatures, with a minimum dipping to -9°C (17°F) and an average of only 5°C (41°F). It also brings increased precipitation, totaling 84 mm (3.3 in) over 13 days, alongside higher humidity at 85%. For more details about the weather patterns in November, refer to Walla Walla weather in November.
September and December present striking contrasts in weather patterns. In September, temperatures fluctuate more dramatically, ranging from a brisk minimum of 1°C (35°F) to a scorching maximum of 36°C (97°F), with an average of 17°C (62°F). This month sees relatively low precipitation at just 25 mm (1.0 in) over four days, accompanied by a moderate humidity level of 58%. In contrast, December ushers in much colder temperatures, with lows plummeting to -14°C (6°F) and a chillier average of 1°C (34°F), all while capping out at a milder maximum of 18°C (65°F). Precipitation rises significantly to 93 mm (3.7 in) spread across 15 days, significantly increasing humidity to 87%. The overall dampness and cold of December certainly create a very different atmosphere compared to the warmth and dryness of September. For more detailed insights into December weather, you can visit Walla Walla weather in December.
As September unfolds in Walla Walla, it marks a noticeable shift in the weather, blending the remnants of summer warmth with the early whispers of autumn. With striking maximum temperatures reaching up to 36°C (97°F), this month presents a remarkable warmth that is gradually tempered by cooler evenings. The average temperature settles at a comfortable 17°C (62°F), while occasional cooler dips remind us of the seasonal transition. Rainfall is minimal, averaging around 25 mm over just a few days, contributing to the dry and pleasant conditions typical of early fall. The moderate humidity of 58% further enhances the overall comfort, making September an ideal time to experience the stunning landscapes and vibrant vineyards of the region. For a deeper understanding of the weather patterns throughout the year, visit Walla Walla Climate.