Last updated: February 24, 2025
In September, Friday Harbor experiences a gentle transition into autumn with maximum temperatures reaching 20°C (68°F) and an average temperature of 13°C (57°F). With nighttime lows usually around 11°C (51°F), visitors can expect mild evenings. During this month, the area sees approximately 68 mm (2.7 in) of rainfall spread over 9 days, contributing to a humidity level of 76% that enhances the lush, green landscape. This combination of weather elements makes September an ideal time to enjoy the beautiful scenery and vibrant wildlife that Friday Harbor has to offer.
In September, Friday Harbor experiences a gentle transition as summer wanes, with temperatures showcasing a comfortable range that entices outdoor enthusiasts. The minimum temperature settles at around 11°C (51°F), while the average hovers at 13°C (57°F), peaking at a pleasant 20°C (68°F). This mild climate, characterized by minimal fluctuations compared to the preceding months, makes September an inviting period for exploring the natural beauty of the area before the cooler autumn air sets in. As the month unfolds, locals and visitors alike relish the crisp air and the last vestiges of summer warmth, perfect for enjoying activities like hiking and whale watching amidst spectacular coastal scenery.
September in Friday Harbor witnesses a notable shift as the summer dry spell gives way to a more balmy, yet wetter season. With an average precipitation of 68 mm (2.7 in) spread across 9 days, it marks a spike from the minimal rainfall of July and August, which recorded just 16 mm (0.6 in) and 15 mm (0.6 in), respectively. This transition hints at the onset of fall, setting the stage for the wetter months ahead, as October typically brings 128 mm (5.1 in) and further increases in precipitation days. The gradual rise in rainfall during September reflects nature’s rhythm, as the lush landscapes of Friday Harbor prepare for the more robust rains that characterize the upcoming months.
September marks a subtle transition in humidity levels in Friday Harbor, with the percentage dipping to 76%, the lowest of the year. This decline follows the summer months, where humidity reached a peak of 84% in July and certainly 77% in August. The trend reveals a gradual easing of moisture in the air as the region shifts from the warm embrace of summer into the crispness of fall. Interestingly, this decrease sets the stage for an upcoming rise, as October sees humidity climb back to 88%. Overall, September serves as a pivotal month, bridging the gap between the warm summer and the wetter months ahead.
In September, Friday Harbor experiences a UV Index of 7, categorizing it as high and making sun protection essential, with a burn time of 25 minutes for fair-skinned individuals. This marks a slight decrease from the summer months, where UV levels peaked at 9, yet it remains significantly elevated, requiring caution during outdoor activities. As the transition into autumn unfolds, the UV Index gradually decreases; however, September still demands vigilance against sun exposure. This trend underscores the importance of adjusting sun safety practices as the seasons change. For more detailed insights, check out the Friday Harbor UV Index.
UV Risk Categories
As summer wanes and autumn approaches, September in Friday Harbor offers a delightful balance of warmth and light. With 265 hours of sunshine, this month marks a graceful transition from the radiant highs of July and August, which boast impressive totals of 390 and 351 hours, respectively. The sun's embrace begins to soften, yet September still shines brighter than the preceding months of October and November. This gentle decline after the peak summer makes September an ideal time for outdoor activities, as daylight lingers just long enough to savor the beauty of the changing seasons. As nature begins its shift towards fall, Friday Harbor basks in the golden hues of autumn, creating picturesque moments under a still-generous sky.
In September, Friday Harbor experiences a notable shift in sunny weather, boasting a 37% chance of sunshine. This marks a decline from the vibrant summer months of July and August, which enjoy probabilities of 77% and 56% respectively. As the season transitions into fall, the likelihood of clear skies decreases, reflecting a seasonal pattern where sunny days become less prevalent. Compared to the earlier months of the year, such as April's 55% and May's 46%, September offers a more moderate forecast, suggesting a blend of lingering summer warmth with the encroaching autumn chill. Overall, while September still holds promise for sunny moments, it's a reminder of the approaching change in weather dynamics.
As summer fades into autumn, September in Friday Harbor brings a gentle shift in daylight hours, offering about 12 hours of sunlight. Following the peak of 16 hours in June, daylight gradually reduces, reflecting the transition into the cooler months. This decline mirrors the pattern established earlier in the year, where longer days in May and June provide a contrast to the shortest days experienced in winter. September's sunlight still embraces the warmth of late summer, but hints at the approaching autumn chill, creating a balanced ambiance that invites outdoor exploration while reminding us of the changing seasons ahead.
As summer gracefully transitions into autumn, September in Friday Harbor witnesses a gentle breeze, with average wind speeds lingering around 4.0 m/s (9 mph). This represents a mild drop from the slightly more robust winds of August, highlighting the calm before the gustier months ahead. After enjoying the relatively consistent and moderate winds of summer, September’s gentle air invites outdoor explorations and tranquil moments by the waterfront. As the seasons shift, wind speeds will begin to rise again, paving the way for the brisker conditions characteristic of autumn, with October bringing an increase to 5.4 m/s (12 mph), heralding the arrival of more dynamic weather patterns as November and December approach.
The weather in Friday Harbor 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 Friday Harbor and find detailed weather information for every month.
The weather in September is generally milder and more pleasant compared to January, with temperatures ranging from a minimum of 11°C (51°F) to a maximum of 20°C (68°F). In contrast, January experiences much colder temperatures, dipping to a minimum of -3°C (27°F) and reaching a maximum of 11°C (52°F). Additionally, September sees 68 mm (2.7 in) of precipitation over 9 days, while January is significantly wetter, with 143 mm (5.6 in) of rain over 16 days. Humidity levels are also higher in January at 86%, compared to September's 76%. For more detailed information, visit Friday Harbor weather in January.
September weather tends to be more temperate, with average temperatures ranging from 11°C (51°F) to a comfortable maximum of 20°C (68°F), accompanied by relatively moderate precipitation of 68 mm (2.7 in) over about 9 days. In contrast, February brings much colder conditions, with average temperatures between -3°C (27°F) and a maximum of 11°C (52°F). This month also experiences higher rainfall, totaling 126 mm (5.0 in) across approximately 17 days, and increased humidity at 85%. For a detailed look at February weather specifics, check out Friday Harbor weather in February.
When comparing the weather in September and March, notable differences emerge. September tends to be milder, with average temperatures ranging from a minimum of 11°C (51°F) to a maximum of 20°C (68°F), contrasted with March, where temperatures are cooler, averaging between 2°C (35°F) and 12°C (55°F). Additionally, September experiences less precipitation, totaling 68 mm (2.7 inches) over about 9 days, while March sees a higher total of 84 mm (3.3 inches) over approximately 14 days. Humidity levels are also higher in March at 86%, compared to September's 76%. For further details, you can check Friday Harbor weather in March.
In comparing the weather between September and April, September tends to be milder and slightly warmer, with average temperatures ranging from 11°C (51°F) to a maximum of 20°C (68°F). In contrast, April features cooler temperatures, with averages between 4°C (39°F) and 14°C (57°F). While both months see a comparable amount of precipitation, September experiences rain on approximately 9 days, whereas April has a higher frequency with rain on about 13 days. Additionally, April is marked by higher humidity levels, averaging 86%, compared to September's 76%. For more detailed insights, you can check Friday Harbor weather in April.
Comparing the weather in September and May reveals some notable differences. In September, temperatures tend to be slightly warmer, ranging from a minimum of 11°C (51°F) to a maximum of 20°C (68°F), with an average of 13°C (57°F). In contrast, May experiences cooler temperatures, peaking at 18°C (64°F) and averaging 11°C (52°F), with a minimum of 6°C (44°F). Additionally, September sees higher precipitation levels at 68 mm (2.7 in) across 9 days, compared to May’s 39 mm (1.5 in) over 7 days. Humidity levels are also relatively high in both months, with September at 76% and May at 81%. For more detailed information on the weather specific to May, you can visit Friday Harbor weather in May.
When comparing the weather in September and June, we notice some intriguing similarities and differences. Both months have an average temperature of around 13°C (55°F), with maximum temperatures reaching 20°C (68°F) in September and 20°C (69°F) in June. However, September tends to be wetter, with 68 mm (2.7 in) of precipitation over 9 days, compared to June's 32 mm (1.3 in) over just 6 days. Additionally, June's humidity level is slightly higher at 83%, compared to September's 76%. For a more detailed look at the June weather specifics, check out Friday Harbor weather in June.
When comparing the weather in September and July, we see some notable differences. Both months have similar temperature ranges, with September showcasing a minimum of 11°C (51°F), an average of 13°C (57°F), and a maximum of 20°C (68°F), while July's temperatures range from a minimum of 11°C (52°F) to an average of 14°C (58°F) and also peaking at 20°C (68°F). However, September experiences significantly more rainfall, with 68 mm (2.7 in) of precipitation over about 9 days, compared to July's much drier conditions, which see only 16 mm (0.6 in) over 3 days. Additionally, humidity levels are slightly lower in September at 76%, compared to July's 84%. For more insights into July weather, you can check Friday Harbor weather in July.
In comparing the weather between August and September, we notice a slight drop in temperature as September experiences a minimum of 11°C (51°F) and averages around 13°C (57°F), compared to August's minimum of 12°C (55°F) and an average of 15°C (59°F). Both months peak at a maximum of 20°C (68°F), but September brings considerably more precipitation, totaling 68 mm (2.7 in) over 9 days, while August is notably drier with only 15 mm (0.6 in) over 3 days. Additionally, humidity levels remain fairly consistent, with September at 76% and August at 77%. For more detailed weather information specific to August, you can check Friday Harbor weather in August.
September and October present a noticeable shift in weather patterns. In September, temperatures range from a minimum of 11°C (51°F) to a maximum of 20°C (68°F), with an average temperature of 13°C (57°F). The month sees a total precipitation of 68 mm (2.7 in) over 9 days, accompanied by a humidity level of 76%. In contrast, October experiences cooler temperatures, with minimums dropping to 5°C (41°F) and maximums peaking at 15°C (60°F), resulting in a lower average of 11°C (52°F). Additionally, October is wetter, registering 128 mm (5.1 in) of rainfall over 15 days and an increased humidity of 88%. For those interested in the specifics, you can find more details at Friday Harbor weather in October.
September's weather is characterized by milder temperatures, with average highs around 20°C (68°F) and a lower humidity of 76%. In contrast, November brings a noticeable chill, with average temperatures dipping to around 9°C (48°F) and a higher humidity of 87%. Additionally, November sees significantly more precipitation, with 194 mm (7.6 in) over 19 days compared to September's 68 mm (2.7 in) over 9 days. The shift from September to November highlights a transition from a relatively pleasant fall to a much wetter and cooler late autumn season. For more details, check out Friday Harbor weather in November.
September's weather tends to be milder, with average temperatures ranging from a minimum of 11°C (51°F) to a maximum of 20°C (68°F). It experiences relatively moderate precipitation of 68 mm (2.7 in) over about 9 days and a humidity level of 76%. In contrast, December brings a significant drop in temperatures, with an average ranging from a chilly -7°C (20°F) to a more moderate 12°C (54°F). The month is also much wetter, featuring 161 mm (6.3 in) of precipitation spread over 18 days, alongside increased humidity at 87%. For a closer look at what the weather is like during December, visit Friday Harbor weather in December.
As summer gracefully fades into autumn, September in Friday Harbor brings a noticeable shift in weather patterns. The warmth of previous months gives way to cooler temperatures, with an average climate that invites cozy sweaters and scenic walks along the waterfront. This month is characterized by increased precipitation, as occasional rain showers become more frequent, contributing to the vibrant fall foliage. The humidity remains relatively high, creating a soft, misty atmosphere that complements the stunning views of the surrounding landscape. For those looking to embrace the transition into autumn, September offers a unique charm that sets it apart from the sun-drenched months of summer. Discover more about the area's changing weather by visiting Friday Harbor Climate.