Last updated: February 24, 2025
Experience the captivating September weather on Bainbridge Island, United States, where the transition from summer to autumn creates a delightful climate. With temperatures reaching a maximum of 28°C (83°F) and an average of 16°C (62°F), the island offers a pleasant warmth ideal for outdoor activities. However, as the month progresses, you may encounter a cooler minimum of 9°C (48°F). Prepare for occasional rain, with 84 mm (3.3 in) of precipitation spread across 13 days, contributing to the lush, vibrant landscape. Coupled with a humidity level of 74%, these conditions foster a refreshing and invigorating atmosphere that highlights the natural beauty of this picturesque destination.
As September rolls into Bainbridge Island, temperatures begin to signal the subtle transition from summer to fall. With minimums averaging around 9°C (48°F) and maximums reaching a pleasant 28°C (83°F), this month strikes a balance that invites outdoor exploration. The average temperature of 16°C (62°F) offers a comfortable climate, perfect for enjoying the island's natural beauty. Notably, while September still retains some vestiges of summer warmth, it also hints at the cooler days ahead, as evidenced by the significant drop in temperatures that will soon follow in October. By observing this month’s climate trends, visitors can appreciate the lingering warmth while preparing for the autumnal embrace that is just around the corner.
In September, Bainbridge Island experiences a notable shift in precipitation patterns as summer gently gives way to autumn. The month sees an average rainfall of 84 mm (3.3 in), a significant uptick compared to the drier summer months of July and August, which recorded only 26 mm (1.0 in) and 25 mm (1.0 in) respectively. With 13 rainy days, September marks a transition into a wetter season, paving the way for the higher precipitation levels expected in the following months, such as October and November. This month serves as a reminder of the Pacific Northwest's characteristic climate, where the lush greenery is often sustained by seasonal rains. As the days grow shorter, the island prepares for the more substantial rainfall that awaits in the heart of fall.
As summer draws to a close, September on Bainbridge Island sees a slight uptick in humidity, settling at 74%. This marks a modest increase from the drier conditions experienced in August, which recorded a low of 73%. The transition into autumn brings a gradual rise in humidity levels, contributing to a softening air quality that has a refreshing effect after the warmer months. Notably, humidity remains significantly lower compared to the winter months, where it peaks at 87% in December. Overall, September embodies a delicate balance, bridging the gap between the dryness of summer and the wetter, cooler days of autumn ahead.
As summer transitions into autumn, the UV Index in Bainbridge Island shows a notable shift in September, with a moderate reading of 7, placing it in the high exposure category. This increase from the lower indices earlier in the year reflects the waning summer sunshine but still demands attention, as residents can experience burn times of around 25 minutes. The region has seen consistently high UV levels from May through August, peaking in June and July with indices of 9. However, as days shorten in the fall, the UV Index drops, hinting at a return to more moderate levels by October. It's essential to stay mindful of UV exposure, especially during this transitional month, and to be aware of evolving trends throughout the year. For more information, check the detailed forecast at Bainbridge Island UV Index.
UV Risk Categories
As summer winds down, September graces Bainbridge Island with a generous 254 hours of sunshine, maintaining the warm glow that lingers from the high-energy summer months. This period marks a notable transition, with sunshine hours tapering from 361 hours in July and 330 hours in August, yet still far surpassing the gloom of the winter months ahead. The trend reveals a steady progression from the bare beginnings of January's 80 hours to the vibrant exuberance of late summer, creating a perfect backdrop for outdoor exploration and reflection as nature prepares for the more subdued autumn. With each passing month, the island shifts from bright summer skies to a calm autumnal palette, offering a unique charm that highlights the beauty of change.
As summer transitions into fall, the likelihood of sunny weather in Bainbridge Island, Washington, begins to shift. September, with a 36% chance of sun, marks a noticeable decline from the peak of 67% in July but maintains a better outlook than the dreary winter months that average around 15-17%. With this moderate increase in cloud cover, September still offers opportunities for some beautiful sunny days, especially compared to the rainier October that follows. This trend highlights the fleeting warmth of late summer and the onset of autumn, making September a perfect time to enjoy the island's natural beauty before the wetter months set in.
As September unfolds in Bainbridge Island, the days begin to shorten, offering about 12 hours of daylight. After basking in the long, sun-soaked days of summer, which peaked at 15 hours in June, residents and visitors alike now notice the gradual transition into fall. The light starts to recede after the vibrant summer months, where daylight lingered late into the evening, a stark contrast to the early sunsets expected in October, with only 10 hours on the horizon. This gradual decline, beginning in August with 14 hours, signifies nature's shift towards the cozier, more introspective months ahead. Embracing the beauty of this transition can make the shortening days feel rich and rewarding, inviting opportunities for reflection and connection as we welcome the autumn season.
As September rolls in on Bainbridge Island, the average wind speed experiences a gentle uptick to 2.9 m/s (6 mph), hinting at the transition towards more brisk autumn breezes. Throughout the summer months, the winds have been relatively calm, reaching a low of 2.1 m/s (5 mph) in July. However, September marks a subtle shift back towards the more invigorating speeds of the earlier months of the year. This gradual increase paves the way for October's expected gustier conditions, where winds rise to 3.6 m/s (8 mph) and beyond. The refreshing winds of September not only invigorate the air but also serve as a reminder of the seasonal changes in full swing.
The weather in Bainbridge Island 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 Bainbridge Island and find detailed weather information for every month.
The weather in September is generally milder compared to January, with average temperatures ranging from a minimum of 9°C (48°F) to a maximum of 28°C (83°F). September typically sees about 84 mm (3.3 inches) of precipitation over 13 days and has a humidity level of 74%. In contrast, January experiences much colder temperatures, averaging between -3°C (26°F) and 14°C (57°F). This winter month is significantly wetter, with 163 mm (6.4 inches) of precipitation spread across 16 days and a higher humidity of 86%. For more detailed information on January's weather, you can check Bainbridge Island weather in January.
When comparing the weather in September and February, notable contrasts emerge. September experiences a milder climate with average temperatures ranging from a minimum of 9°C (48°F) to a maximum of 28°C (83°F), making it a much warmer month overall with 84 mm (3.3 in) of precipitation over 13 days and a humidity level of 74%. In stark contrast, February is significantly cooler, with average temperatures peaking at only 13°C (55°F) and dipping as low as -5°C (24°F). This month also sees more rainfall, totaling 142 mm (5.6 in) across 20 days, along with a slightly higher humidity of 84%. For more insights into the winter weather, check out Bainbridge Island weather in February.
When comparing the weather in September and March, September typically offers milder temperatures, ranging from a minimum of 9°C (48°F) to a pleasant maximum of 28°C (83°F), with an average of 16°C (62°F). In contrast, March features cooler conditions, with temperatures starting at 0°C (32°F) and peaking at 22°C (71°F), averaging just 8°C (46°F). Although September experiences less rainfall, with 84 mm (3.3 inches) over 13 days, March is wetter, receiving 111 mm (4.4 inches) across 17 days. Additionally, humidity is generally higher in March at 85% compared to September's 74%. For a more detailed look at March weather, you can visit Bainbridge Island weather in March.
When comparing the weather in September and April, notable differences emerge in both temperature and precipitation patterns. September boasts a higher average temperature of 16°C (62°F), with maximums reaching up to 28°C (83°F), while April's average is cooler at 10°C (50°F), peaking at 21°C (70°F). Precipitation levels are only slightly higher in April, with 96 mm (3.8 in) over 15 days compared to September's 84 mm (3.3 in) across 13 days. Additionally, April experiences a higher humidity level of 83% versus September's 74%. For more details about April weather, you can check out Bainbridge Island weather in April.
When comparing the weather in September and May, both months showcase a range of temperatures with September generally being warmer. In September, the temperatures can range from a minimum of 9°C (48°F) to a maximum of 28°C (83°F), with an average of 16°C (62°F). In contrast, May features cooler temperatures, with highs reaching up to 25°C (77°F) and an average of 13°C (56°F). Precipitation levels are slightly higher in September at 84 mm (3.3 in) over 13 days, compared to May's 69 mm (2.7 in) over 12 days. Additionally, May has a higher humidity level of 84%, compared to September's 74%, making the latter feel a bit more comfortable despite the increased warmth. For more detailed information about the weather in May, you can visit Bainbridge Island weather in May.
In comparing the weather of September and June, both months share a similar minimum temperature of 9°C (48°F) and an average temperature around 16°C (62°F). However, June experiences higher maximum temperatures, reaching up to 33°C (92°F), compared to September's peak of 28°C (83°F). Additionally, June has less precipitation, totaling 65 mm (2.6 in) over 11 days, while September sees more rainfall at 84 mm (3.3 in) across 13 days. The humidity is slightly higher in June, at 84%, compared to September's 74%. For more detailed information, you can check Bainbridge Island weather in June.
In comparing the weather between September and July, September experiences a broader range of temperatures, with a minimum of 9°C (48°F) and an average of 16°C (62°F), while July's minimum is slightly higher at 12°C (54°F), with an average of 19°C (66°F). Both months share the same maximum temperature of 28°C (83°F). However, September is wetter, with 84 mm (3.3 in) of precipitation over 13 days, compared to July's much drier conditions that see only 26 mm (1.0 in) over just 6 days. Humidity is slightly higher in July at 82% versus 74% in September. For more details, you can check out Bainbridge Island weather in July.
When comparing the weather of September to that of August, it's evident that September experiences cooler temperatures, with a minimum of 9°C (48°F) compared to August's minimum of 12°C (54°F). The average temperature in September is 16°C (62°F), which is notably lower than August's average of 19°C (67°F). Additionally, September sees a significant increase in precipitation, with 84 mm (3.3 in) over 13 days of rain, while August has only 25 mm (1.0 in) over 7 days. Humidity levels remain quite similar, at 74% in September and 73% in August. For more information on August weather specifics, you can check this link: Bainbridge Island weather in August.
In September, the weather tends to be warmer, with average temperatures ranging from a minimum of 9°C (48°F) to a maximum of 28°C (83°F). However, as the month rolls into October, temperatures drop significantly, with averages between 2°C (36°F) and 22°C (73°F). Additionally, October sees increased rainfall, with 136 mm (5.4 inches) of precipitation over 16 days compared to September's 84 mm (3.3 inches) over 13 days. This shift also brings a rise in humidity levels, climbing to 83% in October from 74% in September. For more detailed insights about October's climate, check out Bainbridge Island weather in October.
In comparing the weather of September and November, there are notable differences in temperature and precipitation. September enjoys milder conditions, with temperatures ranging from a minimum of 9°C (48°F) to a maximum of 28°C (83°F), averaging around 16°C (62°F). In contrast, November brings a significant drop in temperatures, with a minimum of 2°C (35°F) and a maximum of just 16°C (61°F), averaging only 9°C (48°F).
Additionally, November experiences much higher precipitation, totaling 168 mm (6.6 in) over 18 days, compared to September's 84 mm (3.3 in) over 13 days. The humidity also increases in November, reaching 86%, compared to September's 74%. For more details on the weather conditions during November, check out Bainbridge Island weather in November.
The weather in September generally features milder temperatures, with a minimum of 9°C (48°F), an average of 16°C (62°F), and a maximum of 28°C (83°F). This month experiences less precipitation, totaling 84 mm (3.3 in) over about 13 days, and humidity is relatively moderate at 74%. In contrast, December brings significantly colder conditions, with temperatures ranging from a minimum of -5°C (24°F) to a maximum of 13°C (56°F) and an average of just 6°C (43°F). Precipitation increases to 179 mm (7.1 in) across 18 days, accompanied by higher humidity levels at 87%. For more detailed information about December weather, visit Bainbridge Island weather in December.
As September rolls in, Bainbridge Island experiences a notable transition from the summer heat to the crispness of fall. With temperatures averaging a mild 16°C (62°F) and a maximum peak of 28°C (83°F), this month offers a comfortable climate that’s distinct from the high heat of July and August. However, it also marks an increase in precipitation, with around 84 mm falling over 13 days, signaling the onset of wetter weather. The humidity at 74% adds to the freshness in the air, creating a unique blend of warmth and moisture that sets September apart from the drier summer months. For more detailed insights on seasonal variations, visit the comprehensive guide on Bainbridge Island Climate.