September Weather in Snoqualmie, United States

Last updated: February 24, 2025

In Snoqualmie, United States, September brings a vibrant transition into autumn, with temperatures ranging from a warm maximum of 31°C (87°F) to a cool minimum of 3°C (37°F). The average temperature sits comfortably at 14°C (57°F), making it a pleasant time for outdoor activities amid the changing foliage. However, prepare for occasional rain, as the area experiences about 128 mm (5.1 in) of precipitation over 13 days throughout the month, contributing to the lush landscape. With humidity levels at 62%, September in Snoqualmie offers a refreshing blend of warmth and moisture, perfect for embracing the beauty of the season.

September Temperature in Snoqualmie

In Snoqualmie, United States, September marks a delightful transition into early autumn, characterized by mild temperatures and a touch of lingering summer warmth. With minimums around 3°C (37°F) and averages of 14°C (57°F), the month enjoys pleasant days where highs reach up to 31°C (87°F). This gradual cooling is a stark contrast to the peak summer heat, showcasing a remarkable drop from August’s extremes. As day fades into night, the crispness in the air hints at the approaching fall, making September a perfect time for outdoor adventures surrounded by the changing foliage. This month serves as a gentle reminder of the shifting seasons, where sunny afternoons still invite exploration.

September Weather in Snoqualmie: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Snoqualmie, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec353439455257616256464035
Data source: Temperature data for Snoqualmie 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.

September Precipitation in Snoqualmie

September in Snoqualmie marks a noticeable shift in precipitation patterns as summer gives way to autumn. With 128 mm (5.1 in) of rain, this month experiences a considerable increase compared to the drier months of July and August, which recorded only 38 mm (1.5 in) and 29 mm (1.1 in) respectively. The rain falls over 13 days, indicating a return of the wetter weather typical for the Pacific Northwest. This uptick not only prepares the landscape for the upcoming months but also highlights a seasonal transition, setting the stage for October's hefty 250 mm (9.8 in), as the region braces for the more persistent rains of fall. Overall, September serves as a bridge, blending the remnants of summer's dry spell with the looming autumn deluge, creating a lush backdrop that characterizes the natural beauty of Snoqualmie.

September Precipitation Trends in Snoqualmie

The chart displays monthly precipitation patterns in Snoqualmie, with values for each month alongside September's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec239296182170106983829128250276284
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Snoqualmie

In Snoqualmie, the trend of humidity levels takes a notable dip in September, averaging a refreshing 62%. This marks a significant decline from the humid summer months, where August boasts a high of 63%. As the region transitions into autumn, the decrease reflects a shift in weather patterns, providing a brief respite from the typically damp conditions experienced earlier in the year. Following September, humidity levels begin to rise again, climbing steeply to 83% in October and peaking at 89% in November. This cyclical fluctuation creates a rhythm of seasonal changes that defines Snoqualmie's distinct climate throughout the year.

September Average Humidity in Snoqualmie

This chart illustrates the average monthly humidity levels in Snoqualmie, with September's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how September's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%87%84%81%82%79%63%62%83%89%88%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Snoqualmie

As September rolls into Snoqualmie, the UV Index drops to 7, indicating a high exposure category, which allows for a 25-minute burn time. This marks a slight decline from the peak summer months, where the UV Index stayed consistently at 9, categorizing it as very high. The trend points towards a reduction in UV intensity as the region transitions into fall, yet it remains crucial to stay vigilant with sun protection during these late-summer days. With UV levels experiencing this fluctuation, it's a good reminder for residents and visitors to monitor the changing UV Index throughout the month. For more detailed information on current conditions, visit Snoqualmie UV Index.

Maximum UV Index Levels in Snoqualmie for September

The chart shows the monthly maximum UV Index (UVI) for Snoqualmie in September, 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.
JanFebMarAprMayJunJulAugSepOctNovDec236799997532
Data source: Snoqualmie September 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.

September Sunshine in Snoqualmie

As summer transitions into fall, September in Snoqualmie offers a delightful blend of sunny days, boasting 247 hours of sunshine. This month captures the tail end of the vibrant summer, where the sunlight begins to soften, yet the days remain pleasantly bright. Notably higher than the winter months, September's sunshine hours show a significant decrease from the sun-drenched peaks of July and August, which recorded 357 and 326 hours, respectively. However, compared to earlier months, such as January with only 75 hours, September shines brightly, signaling a gradual retreat toward the cooler days of autumn. This seasonal shift allows residents and visitors alike to bask in the golden hues of early fall while enjoying outdoor activities amidst the stunning Pacific Northwest backdrop.

Monthly Sunshine Duration in Snoqualmie: September Highlighted

The September sunshine duration represents the total number of hours Snoqualmie experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec75h100h179h224h287h295h357h326h247h167h104h81h
Data source: Snoqualmie September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Snoqualmie During September

As summer fades, September in Snoqualmie brings a notable transition in weather patterns. While the sunshine is still present, with a 37% chance of clear skies, it's a significant dip from the peak of summer. This month marks a gradual shift towards more overcast days as the region prepares for the fall. Historically, September offers a balance, where lingering warmth meets the encroaching clouds, providing residents and visitors alike with ample opportunities to enjoy the outdoors before autumn fully sets in. Thus, you can still delight in sunny days, but be prepared for the unpredictability that the changing season brings.

Percentage of Sunny Days in September in Snoqualmie

The chart illustrates the percentage of sunny days in Snoqualmie throughout the year, with September 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 Snoqualmie experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec16%10%29%49%33%53%62%46%37%22%14%10%
Data source: Snoqualmie September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Snoqualmie in September

As summer fades, September in Snoqualmie brings a subtle shift in daylight, offering about 12 hours of sunlight. This represents a gentle decline from August's generous 14 hours, as the days grow shorter on the approach to autumn. The trend highlights a gradual transition throughout the year, starting from 8 hours in January, peaking at 15 hours in both May and June, and then steadily decreasing as the seasons change. This cyclical pattern of daylight not only marks the changing seasons but also invites residents to embrace the cozy autumn atmosphere that lies ahead.

Average Daylight Hours in Snoqualmie for September

The chart illustrates the variation in daylight duration in Snoqualmie throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec8h 55m10h 16m11h 57m13h 40m15h 8m15h 53m15h 28m14h 9m12h 29m10h 47m9h 16m8h 29m
Data source: Snoqualmie daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Snoqualmie

In September, the average wind speed in Snoqualmie drifts gently at 1.8 m/s (4 mph), maintaining a calm atmosphere that characterizes the tail end of summer. Over the months, a noticeable trend emerges as the wind speeds exhibit a gradual decline in the warmer months, reaching their lowest points in July and August before slightly picking up in October. This subtle lull in wind during September allows for the serene enjoyment of the changing foliage and the crisp approach of autumn. As the year progresses, the winds roar back to life in November, reminding us of nature's cyclical rhythms, transitioning smoothly from the calm of September to the brisk breezes of fall.

Average September Wind Speed in Snoqualmie

The chart displays monthly wind speed patterns in Snoqualmie, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec2.32.81.92.02.01.81.61.71.8 m/s2.12.82.2
Data source: Snoqualmie September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Snoqualmie Compares to Other Months

The weather in Snoqualmie 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 Snoqualmie and find detailed weather information for every month.

September and January exhibit stark contrasts in weather conditions. In September, temperatures range from a mild 3°C (37°F) at night to a warm 31°C (87°F) during the day, with an average temperature of 14°C (57°F). This month experiences 128 mm (5.1 in) of precipitation over 13 days, along with a humidity level of 62%. In contrast, January is much cooler, with temperatures plunging to a minimum of -15°C (6°F) and peaking at only 11°C (51°F), leading to an average temperature of just 2°C (36°F). This winter month receives more precipitation, totaling 239 mm (9.4 in) over 17 days, and boasts a higher humidity level of 86%. For more detailed insights, you can refer to this link: Snoqualmie weather in January.

September and February present striking contrasts in weather conditions. In September, temperatures range from a minimum of 3°C (37°F) to a maximum of 31°C (87°F), with an average of 14°C (57°F). The month sees about 128 mm (5.1 in) of precipitation over approximately 13 days, all while maintaining a humidity level of 62%. On the other hand, February experiences much colder weather, with temperatures dipping to a minimum of -14°C (7°F) and peaking at 13°C (56°F), averaging around 1°C (34°F). This month is notably wetter, with 296 mm (11.6 in) of precipitation spread across 21 days and a higher humidity of 86%. For more details on the weather in February, check out Snoqualmie weather in February.

When comparing the weather in September and March, it's evident that each month presents its own unique characteristics. September typically enjoys warmer temperatures, with average highs reaching 31°C (87°F), while March sees a cooler range, with average highs only reaching 18°C (65°F). In terms of precipitation, March is generally wetter, accumulating 181 mm (7.1 in) over 19 days compared to September's 128 mm (5.1 in) across 13 days. Additionally, March experiences much higher humidity at 87%, while September’s humidity hovers around 62%. For more detailed information on March conditions, you can visit Snoqualmie weather in March.

When comparing the weather in September and April, we notice some significant differences. September tends to be warmer, with temperatures ranging from a minimum of 3°C (37°F) to a maximum of 31°C (87°F) and an average of 14°C (57°F). In contrast, April experiences cooler temperatures, with a minimum of -6°C (21°F) and a maximum of 26°C (79°F), averaging only 7°C (45°F). Precipitation in April is higher at 170 mm (6.7 in) over 17 days compared to September's 128 mm (5.1 in) over 13 days. Additionally, the humidity is noticeably higher in April at 84%, compared to September's 62%. For more detailed information, you can refer to Snoqualmie weather in April.

In September, temperatures can vary significantly, with a minimum of 3°C (37°F) and a maximum reaching up to 31°C (87°F), averaging around 14°C (57°F). The month experiences about 128 mm (5.1 in) of precipitation over approximately 13 days, accompanied by a moderate humidity level of 62%. In contrast, May typically has cooler temperatures, with a minimum of 0°C (32°F) and a maximum of 27°C (81°F), averaging 11°C (52°F). Precipitation in May is slightly less, totaling 106 mm (4.2 in) over around 15 days, but humidity is higher, peaking at 81%. This difference in temperature and humidity highlights the transition from spring to early autumn. For more details, check out Snoqualmie weather in May.

September tends to be a transition month with a wider range of temperatures, from a cool minimum of 3°C (37°F) to a warm maximum of 31°C (87°F). The average temperature remains constant at 14°C (57°F), but it experiences more rainfall, totaling 128 mm (5.1 in) over 13 days and a moderate humidity level of 62%. In contrast, June features a similar minimum temperature of 3°C (38°F) and an average temperature of 14°C (57°F), but it can reach higher maximums of up to 39°C (103°F). Precipitation in June is slightly lower at 98 mm (3.9 in) over the same number of days, although the humidity is higher at 82%. For more details on the June weather, you can visit Snoqualmie weather in June.

When comparing the weather in September to that of July, notable differences emerge. September experiences a wider temperature range, with minimums dropping to 3°C (37°F) and maximums reaching up to 31°C (87°F), averaging around 14°C (57°F). In contrast, July is slightly warmer, with minimum temperatures at 6°C (43°F) and maximums peaking at 32°C (89°F), yielding an average of 16°C (62°F). Additionally, September sees significantly more precipitation, totaling 128 mm (5.1 inches) over 13 days, compared to July's 38 mm (1.5 inches) over just 8 days, highlighting the wetter conditions typical of early fall. The humidity is also lower in September at 62%, while July has higher humidity levels at 79%. For more detailed insights about July weather, you can visit Snoqualmie weather in July.

Comparing the weather between September and August reveals notable differences in temperature and precipitation patterns. September experiences a wider temperature range, with a minimum of 3°C (37°F) and a maximum of 31°C (87°F), leading to an average temperature of 14°C (57°F). In contrast, August has a slightly warmer average of 17°C (62°F) and a higher maximum of 34°C (94°F), although it starts from a higher minimum temperature of 5°C (42°F). Precipitation also plays a significant role, with September seeing much more rainfall at 128 mm (5.1 in) over 13 days, compared to August’s relatively dry conditions with just 29 mm (1.1 in) across 6 days. Humidity levels are similar, with September at 62% and August at 63%. For a more detailed look at August weather, check out Snoqualmie weather in August.

In September, the weather features a broader temperature range with minimums around 3°C (37°F) and highs reaching up to 31°C (87°F), resulting in an average temperature of 14°C (57°F). This month also experiences a fair amount of precipitation, totaling 128 mm (5.1 in) over 13 days, along with a humidity level of 62%. In contrast, October brings a significant drop in temperatures, with minimums plummeting to -6°C (22°F) and averages around 8°C (46°F). The month sees increased precipitation, totaling 250 mm (9.8 in) across 16 days, and a rise in humidity to 83%. For more details on October weather, check out Snoqualmie weather in October.

The weather in September is characterized by a broader temperature range, with minimums around 3°C (37°F) and maximums reaching up to 31°C (87°F), resulting in an average of 14°C (57°F). In contrast, November brings significantly colder temperatures, with a minimum of -5°C (23°F) and an average of just 5°C (40°F). Moreover, November experiences much more precipitation—276 mm (10.9 in) over 20 days—compared to September's 128 mm (5.1 in) over 13 days. The humidity also rises dramatically in November to 89%, making it feel considerably chillier than the milder, more variable September weather. For more details on November weather, you can check this link: Snoqualmie weather in November.

In comparing the weather of September to December, it’s clear that December experiences much colder temperatures and higher precipitation levels. September enjoys an average temperature of 14°C (57°F), with daytime highs reaching up to 31°C (87°F), while December’s average drops to a chilly 2°C (36°F) and can fall as low as -13°C (9°F). Rainfall is also more frequent in December, with 284 mm (11.2 in) of precipitation over 20 days compared to September's 128 mm (5.1 in) over 13 days. Additionally, December is notably more humid, averaging 88%, compared to September’s 62%. For more details on December conditions, check out Snoqualmie weather in December.

Compare Snoqualmie's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Snoqualmie

As September rolls in, Snoqualmie's weather begins to shift, showcasing a distinct transition from the summer warmth to the crispness of fall. With maximum temperatures often reaching into the low thirties, the days still bask in sunshine, yet the average dips to a refreshing 14°C, hinting at the cooler nights to come. This month experiences heightened precipitation, with nearly half the month seeing rain, contributing to a more humid environment. In contrast to the drier summer months, the blend of warmth and moisture sets the stage for spectacular autumn scenery. For a deeper dive into Snoqualmie's unique climate patterns, explore Snoqualmie Climate.