September Weather in Girdwood, United States

Last updated: February 24, 2025

In Girdwood, United States, September showcases a dynamic climate characterized by an average temperature of 6°C (42°F), with peaks reaching a mild 16°C (61°F) and lows dipping to a brisk -12°C (11°F). This month is marked by substantial precipitation, totaling 192 mm (7.5 in) over approximately 19 days, resulting in a notably humid atmosphere with levels soaring to 96%. As fall approaches, the weather presents a blend of challenges and beauty, making it an intriguing time for both locals and visitors alike.

September Temperature in Girdwood

As September unfolds in Girdwood, the transition from summer to autumn is palpable, with temperatures reflecting a notable drop. The month begins with a brisk chill, presenting a minimum of -12°C (11°F) against an average of 6°C (42°F), and peaks at a moderate 16°C (61°F). Compared to the warmer summer months of July and August, where highs reach up to 26°C (79°F) and 21°C (71°F) respectively, September marks a distinct cool-off. This shift heralds the arrival of fall, where the vibrant landscape begins to take on the stunning hues of autumn foliage, making it a beautiful yet cooling time in Girdwood. Overall, September bridges the gap between summer's warmth and the impending chill of winter, setting the stage for the coming seasonal changes.

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

The chart illustrates September temperature patterns in Girdwood, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec161618303747535042311921
Data source: Temperature data for Girdwood 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 Girdwood

In Girdwood, September marks a significant uptick in precipitation, with an impressive 192 mm (7.5 in) recorded, making it one of the wettest months of the year. This increase follows the already substantial 156 mm (6.1 in) received in August and sets the stage for an even wetter October, which averages 281 mm (11.1 in). Notably, September sees about 19 days of rainfall, contributing to the lush, vibrant landscapes typical of this time of year. As autumn approaches, the trend indicates that while summer may bring sporadic rain, fall delivers a more consistent and bountiful deluge, underscoring Girdwood's reputation as a wet and wild paradise during this transition.

September Precipitation Trends in Girdwood

The chart displays monthly precipitation patterns in Girdwood, 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.
JanFebMarAprMayJunJulAugSepOctNovDec165115131115142107109156192281224268
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Girdwood

In September, Girdwood experiences a notable humidity level of 96%, contributing to the region's lush, green landscapes. The data shows a gradual decline in humidity from the peak of 102% in July, which marks the height of summer, before slightly dipping in August to 100%. This trend indicates a transition into the cooler autumn months, with September maintaining a relatively high humidity, consistent with the earlier months of the year that typically see readings above 90%. As the year progresses into October, humidity levels fall to 91%, hinting at the approaching winter and adding to the area's distinctive charm. Overall, September serves as a bridge month, bridging the summer's moist warmth with the crisp air of autumn.

September Average Humidity in Girdwood

This chart illustrates the average monthly humidity levels in Girdwood, 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.
JanFebMarAprMayJunJulAugSepOctNovDec94%93%91%85%88%95%102%100%96%91%95%96%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Girdwood

As September rolls into Girdwood, the UV Index reflects a notable shift, falling to 4, which categorizes sun exposure as moderate. This decrease from the peak summer months indicates a transition towards milder conditions, with suggested burn time extending to 30 minutes. Compared to the higher indices of 7 seen in both May and July, September offers a more tempered environment for outdoor activities, allowing residents and visitors to enjoy the beautiful Alaskan landscape while still being mindful of sun protection. As the season changes, remember to check for daily updates and stay informed about UV levels throughout the month with Girdwood UV Index.

Maximum UV Index Levels in Girdwood for September

The chart shows the monthly maximum UV Index (UVI) for Girdwood 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.
JanFebMarAprMayJunJulAugSepOctNovDec123576764211
Data source: Girdwood 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 Girdwood

As summer gives way to fall, September in Girdwood offers a gentle decline in sunshine, with 184 hours of light making it a delightful transition month. This shift follows a season of abundant daylight, peaking in June with 311 hours, and slowly receding as the year progresses. While September's sunlight is less than the vibrant heights of summer, it still shines brighter than the winter months ahead, hinting at nature's serene farewells. The gradual descent from summer invites residents and visitors to enjoy the crisp air and stunning autumn landscapes, balancing the fading sun with the promise of the spectacular colors that define this time of year.

Monthly Sunshine Duration in Girdwood: September Highlighted

The September sunshine duration represents the total number of hours Girdwood 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.
JanFebMarAprMayJunJulAugSepOctNovDec53h124h203h263h277h311h292h257h184h123h91h39h
Data source: Girdwood September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Girdwood During September

In Girdwood, United States, September brings a modest 15% chance of sunny weather, mirroring the trends of the two preceding months. As summer transitions to fall, the likelihood of clear skies diminishes significantly from the year's height in March (33%) and April (42%). This gradual decline underscores a seasonal shift, with sunshine becoming increasingly rare as the days shorten and clouds gather. Comparatively, September's sunshine probability closely aligns with other cooler months like October and November, suggesting that while late summer can still offer glimpses of beautiful weather, residents and visitors should brace for the approach of autumn's more overcast days.

Percentage of Sunny Days in September in Girdwood

The chart illustrates the percentage of sunny days in Girdwood 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 Girdwood experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec12%25%33%42%20%16%15%25%15%6%10%15%
Data source: Girdwood September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Girdwood in September

As summer fades and autumn approaches in Girdwood, September marks a noticeable shift in daylight hours. After basking in 19 hours of daylight in June, residents witness a gradual decrease, enjoying 12 hours of sunshine this month. This decline signals the transition from the vibrant long days of summer to the shorter, cozier days that follow. Notably, September retains a good amount of daylight compared to the winter months ahead, where daylight dwindles to a mere 5 hours by December. This rhythmic ebb and flow of light throughout the year not only shapes the landscape but also influences the activities and lifestyle of Girdwood's residents as they prepare for the embrace of fall.

Average Daylight Hours in Girdwood for September

The chart illustrates the variation in daylight duration in Girdwood throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec6h 35m9h 4m11h 53m14h 46m17h 29m19h 3m18h 8m15h 36m12h 46m9h 56m7h 14m5h 41m
Data source: Girdwood daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Girdwood

As September unfolds in Girdwood, the winds stir gently, with an average speed of 1.7 m/s (4 mph), mirroring the steady currents of the summer months. This slight consistency hints at a transitional period, as temperatures begin to cool and the vibrant fall colors emerge. Notably, September maintains the same wind speed as August, suggesting a lingering breeze that carries the essence of summer into autumn. In this serene setting, the calmness of the wind is a reminder that soon, as the seasons shift, Girdwood will experience increasingly tranquil conditions, with average wind speeds tapering off in the months ahead.

Average September Wind Speed in Girdwood

The chart displays monthly wind speed patterns in Girdwood, 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.
JanFebMarAprMayJunJulAugSepOctNovDec1.61.31.31.41.71.91.71.71.7 m/s1.31.11.3
Data source: Girdwood September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Girdwood Compares to Other Months

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

In September, temperatures in Girdwood range from a brisk -12°C (11°F) at night to a mild 16°C (61°F) during the day, with an average of 6°C (42°F). The month also sees substantial rainfall, with 192 mm (7.5 in) of precipitation over 19 days, combined with high humidity levels of 96%. In contrast, January experiences much colder conditions, as temperatures drop significantly, ranging from a minimum of -27°C (-17°F) to a maximum of just 2°C (36°F), averaging -9°C (16°F). Although precipitation is slightly lower at 165 mm (6.5 in), it occurs over fewer days—13 in total—and humidity remains high at 94%. For more details on January weather conditions, check Girdwood weather in January.

September weather is notably milder than February’s, with temperatures ranging from a minimum of -12°C (11°F) to a maximum of 16°C (61°F) and an average of 6°C (42°F). This month also sees significant precipitation, totaling 192 mm (7.5 in) over 19 days, accompanied by high humidity at 96%. In contrast, February experiences much colder conditions, with temperatures dipping to a minimum of -25°C (-13°F) and averaging -9°C (17°F), peaking at just 2°C (35°F). Precipitation in February is lighter, amounting to 115 mm (4.5 in) over 14 days, though the humidity remains relatively high at 93%. For more detailed information, check out Girdwood weather in February.

In comparing the weather of September and March, we find notable differences in temperature and precipitation. September tends to be milder, with temperatures ranging from a minimum of -12°C (11°F) to a maximum of 16°C (61°F), while March is noticeably colder, experiencing minimum temperatures of -25°C (-12°F) and a maximum of just 5°C (42°F). Precipitation patterns also differ; September sees more rainfall at 192 mm (7.5 in) over 19 days, whereas March has 131 mm (5.2 in) over only 12 days. Additionally, humidity levels are slightly higher in September at 96%, compared to March's 91%. For a more detailed look at March conditions, you can check out Girdwood weather in March.

In comparing the weather between September and April, it's evident that September tends to be milder, with average temperatures ranging from a minimum of -12°C (11°F) to a maximum of 16°C (61°F). In contrast, April features colder temperatures, starting at a minimum of -19°C (-2°F) and only reaching a maximum of 11°C (53°F). Additionally, September experiences more precipitation, totaling 192 mm (7.5 in) over 19 days, compared to April's 115 mm (4.5 in) over 14 days. While both months are relatively humid, September's humidity level is notably higher at 96%, compared to April's 85%. For more detailed information, you can check out Girdwood weather in April.

September and May showcase notable differences in weather patterns. September experiences a colder range, with temperatures dropping to a minimum of -12°C (11°F) and averaging 6°C (42°F), while May has milder conditions, featuring a minimum of -5°C (22°F) and an average of 3°C (37°F). Both months share a maximum temperature of 16°C (61°F), yet September receives more precipitation at 192 mm (7.5 in) compared to May's 142 mm (5.6 in), with a higher humidity of 96% versus May's 88%. This makes September feel noticeably more damp and cool. For more details on May weather specifics, check out Girdwood weather in May.

In comparing the weather of September and June, we can see notable differences in temperature and precipitation patterns. September experiences a sharper chill, with average temperatures ranging from a minimum of -12°C (11°F) to a maximum of 16°C (61°F), while June boasts milder conditions, with temperatures varying from -2°C (29°F) to a warm 24°C (75°F). Additionally, September tends to be wetter, accumulating 192 mm (7.5 in) of precipitation over 19 days, compared to June’s 107 mm (4.2 in) over 21 days. Humidity levels remain high in both months, with September at 96% and June slightly lower at 95%. For a closer look at June weather, check out Girdwood weather in June.

September's weather is noticeably cooler than July's, with average temperatures ranging from a chilly 6°C (42°F) to a maximum of 16°C (61°F), while July boasts a warmer average of 11°C (53°F) and highs reaching up to 26°C (79°F). Additionally, September is characterized by a higher degree of precipitation, accumulating 192 mm (7.5 in) over 19 days, in contrast to July's 109 mm (4.3 in) spread over 17 days. The humidity levels also peak in September at 96%, compared to July's slightly lower 102%. This significant difference in climate highlights the transition from the warmer, more vibrant summer months to the cooler, wetter autumn season. For more specific details, check out Girdwood weather in July.

Comparing the weather between September and August reveals notable differences in temperature and precipitation. September experiences a cooler temperature range with a minimum of -12°C (11°F) and a maximum of 16°C (61°F), leading to an average of 6°C (42°F). In contrast, August maintains milder conditions, with temperatures ranging from a minimum of 0°C (33°F) to a maximum of 21°C (71°F) and an average of 10°C (50°F). Additionally, September sees a slight increase in precipitation, totaling 192 mm (7.5 in) over 19 days, compared to August's 156 mm (6.1 in) over 20 days. Humidity levels also differ, with September at 96% and August reaching a humid 100%. For more details on August conditions, you can check Girdwood weather in August.

September and October weather show distinct differences as autumn deepens. In September, temperatures range from a minimum of -12°C (11°F) to a maximum of 16°C (61°F), with an average of 6°C (42°F). This month sees substantial precipitation at 192 mm (7.5 in) over 19 days, accompanied by high humidity at 96%. In contrast, October experiences colder temperatures, with lows dipping to -15°C (4°F) and a high of 13°C (56°F), averaging around 0°C (32°F). Rainfall increases to 281 mm (11.1 in) over 21 days, while humidity decreases slightly to 91%. For more detailed information about conditions, check out Girdwood weather in October.

September and November present stark contrasts in weather conditions. In September, temperatures typically range from a minimum of -12°C (11°F) to a maximum of 16°C (61°F), with an average of 6°C (42°F) and relatively high humidity at 96%. Precipitation is significant, with 192 mm (7.5 in) recorded over 19 days. In contrast, November sees a notable drop in temperature, with minimums plummeting to -27°C (-16°F) and an average temperature of -7°C (19°F). The maximum temperature only reaches 3°C (38°F). While November has slightly higher precipitation at 224 mm (8.8 in), it occurs over fewer days—just 16. The humidity remains quite high at 95%, creating a chilly atmosphere typical of late fall. For more detailed information on weather conditions, you can check Girdwood weather in November.

In September, the weather features a milder temperature range with a minimum of -12°C (11°F), an average of 6°C (42°F), and a maximum of 16°C (61°F). The month sees significant rainfall, totaling 192 mm (7.5 in) over 19 days, while humidity remains high at 96%. In contrast, December experiences much colder conditions, with a minimum of -24°C (-10°F), an average of -6°C (21°F), and a maximum of 5°C (41°F). The precipitation increases to 268 mm (10.6 in) over 23 days, maintaining the same high humidity level of 96%. For more details, you can check out Girdwood weather in December.

Compare Girdwood's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Girdwood

As September unfolds in Girdwood, the weather begins to shift dramatically, transitioning from the warmer, sunnier days of summer to a cooler and more unpredictable climate. This month is marked by a notable increase in precipitation, with frequent rain showers contributing to the lush scenery, even as temperatures dip significantly. With humidity hovering around a remarkable 96%, the air feels particularly crisp and damp, offering a refreshing reminder of the approaching fall. Unlike the balmy summer months, September brings a mix of beautiful fall foliage and the first hints of winter, making it an ideal time to experience Girdwood’s stunning natural beauty. For a deeper understanding of what to expect throughout the year, visit Girdwood Climate.