September Weather in Knik River, United States

Last updated: February 24, 2025

In September, the weather at the Knik River in the United States showcases a transition into the cooler months. With a maximum temperature reaching 18°C (65°F) and an average of 7°C (45°F), the days gradually invite a chill. The thermometer dips to a minimum of -8°C (17°F), hinting at the approaching winter. September is also characterized by a notable precipitation amount of 127 mm (5.0 in) over 18 days, creating a humid atmosphere with humidity levels soaring to 96%. This combination of temperature and moisture fosters an environment rich in autumnal beauty, making it an intriguing time for nature enthusiasts and outdoor adventurers alike.

September Temperature in Knik River

In September, the Knik River region begins to transition towards the cooler months, with temperatures showcasing a noticeable shift. The minimum temperature dips to -8°C (17°F), indicating the onset of fall, while the average hovers around 7°C (45°F), providing a brief reprieve from the summer warmth. The maximum reaches a mild 18°C (65°F), making it one of the last chances to enjoy the outdoors before winter sets in. This month marks a significant cooling trend from the preceding summer, yet still retains a touch of warmth compared to the frigid lows of early winter, signaling the changing seasons and the beauty of nature's cycles.

September Weather in Knik River: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Knik River, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec111519324251565345331717
Data source: Temperature data for Knik River 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 Knik River

In September, Knik River experiences a substantial precipitation level of 127 mm (5.0 in) over 18 days, making it one of the wetter months of the year. This timing marks a slight decrease from August's considerable rainfall of 137 mm (5.4 in), yet it remains consistent with the trend of increasing moisture as summer transitions into fall. The wet conditions pave the way for October’s even higher precipitation, expected to average around 173 mm (6.8 in). This gradual rise in precipitation amounts through late summer into early autumn highlights Knik River's dynamic climate, where the lush landscape thrives under these damp conditions, preparing for the winter chill ahead.

September Precipitation Trends in Knik River

The chart displays monthly precipitation patterns in Knik River, 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.
JanFebMarAprMayJunJulAugSepOctNovDec80747254758389137127173114142
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Knik River

September in Knik River, United States, continues the trend of high humidity characteristic of this region, registering at 96%. This month sees a slight decrease from the peak summer months of August and July, which recorded astonishing humidity levels of 100% and 102%, respectively. The transition from summer to autumn suggests a gradual moderation in moisture levels, yet September remains notably humid compared to the cooler months that follow. Overall, the data reveals Knik River's persistent high humidity, particularly evident during the warmer months, creating a unique atmospheric experience that lingers into early fall.

September Average Humidity in Knik River

This chart illustrates the average monthly humidity levels in Knik River, 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 Knik River

In September, Knik River experiences a UV Index of 4, indicating a moderate exposure level that invites outdoor enthusiasts to enjoy the crisp fall weather while remaining mindful of sun safety. As the UV Index begins to drop from the summer peak of 7 in July, the burn time extends back to 30 minutes, offering a balanced opportunity for leisurely activities without the intense sun stress of earlier months. This trend marks a transition toward lower UV levels, supported by the engaging pattern from May to September, where indices ranged from 6 to 4. As the sun begins to set earlier and its rays soften, residents and visitors should still consider protective measures during midday hours. For a detailed overview of sun safety and UV trends, visit Knik River UV Index.

Maximum UV Index Levels in Knik River for September

The chart shows the monthly maximum UV Index (UVI) for Knik River 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.
JanFebMarAprMayJunJulAugSepOctNovDec113466754211
Data source: Knik River 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 Knik River

As September rolls into Knik River, the sunlight begins to wane after a vibrant summer, yet 186 hours of sunshine ensure that autumn still sparkles with warmth. Following the peak of summer, which saw 313 hours of radiant light in June, the daylight hours gracefully taper off, signifying the transition to cooler months. This gradual decline from August's 259 hours speaks to the often-fluctuating nature of seasonal change in this picturesque region. Despite the decrease, September’s sunshine invites outdoor adventures, as the rich tapestry of fall foliage unfolds, providing a stunning backdrop that highlights the enduring beauty of the Alaskan landscape. Embracing the interplay of light and shadow, this month is a gentle reminder that even as the days shorten, the essence of summer lingers on.

Monthly Sunshine Duration in Knik River: September Highlighted

The September sunshine duration represents the total number of hours Knik River 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.
JanFebMarAprMayJunJulAugSepOctNovDec53h125h206h275h297h313h300h259h186h130h92h40h
Data source: Knik River September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Knik River During September

In Knik River, the likelihood of sunny weather in September stands at a modest 24%, reflecting a trend of gradually diminishing sunshine as summer transitions into fall. Notably, this percentage is on par with June but significantly lower than the more sun-filled months of April and May, which boast chances of around 50% and 29%, respectively. As the year progresses from the peak summer months of July and August, where sunshine dips to 21% and 28%, September’s cooler temperatures contribute to an equally subdued chance of sunny days. This pattern highlights the region's shift toward cloudier skies as autumn approaches, making sun-soaked September days a delightful, if rare, occurrence.

Percentage of Sunny Days in September in Knik River

The chart illustrates the percentage of sunny days in Knik River 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 Knik River experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec27%37%39%50%29%24%21%28%24%14%28%24%
Data source: Knik River September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Knik River in September

As summer transitions into autumn, September in Knik River sees a gentle decline in daylight hours, with the sun gracing the landscape for approximately 12 hours each day. This decrease marks a shift from the long, vibrant days of June and July, which offered nearly 19 hours of sunlight, to the more subdued and contemplative days of fall. Following the peak summer brightness, light gradually wanes, dropping to 15 hours in August before settling into the crisp air of September. This trend begins the annual journey towards shorter days, ultimately leading to the dimmer, winter months ahead, where daylight hours shrink to a mere 5 by December.

Average Daylight Hours in Knik River for September

The chart illustrates the variation in daylight duration in Knik River throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec6h 24m8h 59m11h 53m14h 51m17h 39m19h 19m18h 21m15h 42m12h 47m9h 52m7h 6m5h 28m
Data source: Knik River daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Knik River

As September unfolds in the Knik River region, the breeze begins to whisper hints of autumn, with an average wind speed of 1.3 m/s (3 mph). This slight uptick from the preceding summer months indicates the transition from the calmness of July and August, where winds barely stirred, to a subtle invigorating freshness that the autumn months promise. While the wind maintains a leisurely pace compared to the gustier months of January and November, September’s breezes are a gentle reminder of the changing seasons, setting the stage for the cooler, crisper days ahead. This month’s shift marks a departure from the summer lull, bringing with it the vibrant colors and lively atmosphere that accompany the onset of fall in this scenic part of the United States.

Average September Wind Speed in Knik River

The chart displays monthly wind speed patterns in Knik River, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.21.91.51.41.31.21.21.21.3 m/s1.41.81.8
Data source: Knik River September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Knik River Compares to Other Months

The weather in Knik River 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 Knik River and find detailed weather information for every month.

In September, the weather is considerably milder with temperatures ranging from a minimum of -8°C (17°F) to a maximum of 18°C (65°F), averaging around 7°C (45°F). This month sees significant rainfall, with 127 mm (5.0 in) of precipitation spread over 18 days, and humidity levels at a high 96%. In contrast, January presents an entirely different scene; temperatures plummet to a minimum of -34°C (-28°F) and peak at just 2°C (36°F), averaging -12°C (11°F). Although January receives less precipitation at 80 mm (3.1 in) over 12 days, the humidity remains high at 94%. For a detailed look at the January conditions, check out this link: Knik River weather in January.

In September, temperatures range from a chilly minimum of -8°C (17°F) to a pleasant maximum of 18°C (65°F), with an average of 7°C (45°F). The month experiences significant rainfall, with 127 mm (5.0 in) of precipitation over 18 days and high humidity at 96%, making it feel quite damp. In contrast, February brings much colder conditions, with temperatures plummeting to a minimum of -25°C (-13°F) and only reaching a maximum of 3°C (38°F), resulting in an average temperature of -10°C (15°F). Precipitation decreases to 74 mm (2.9 in) over just 13 days, with humidity slightly lower at 93%. For more details about February weather, you can check Knik River weather in February.

In comparing the weather between September and March, notable differences emerge in temperature and precipitation. September experiences milder temperatures, with a minimum of -8°C (17°F) and an average of 7°C (45°F), peaking at a comfortable 18°C (65°F). In contrast, March is significantly colder, featuring minimum temperatures of -25°C (-12°F) and an average of -7°C (20°F), with a maximum of just 8°C (46°F). Precipitation levels also vary, as September records 127 mm (5.0 in) over 18 days, while March sees less rain, totaling 72 mm (2.8 in) across 12 days. Humidity remains high in both months, but slightly decreases from September's 96% to March's 91%. For a closer look at the unique weather conditions in March, you can explore Knik River weather in March.

When comparing the weather in September and April, notable differences in temperature and precipitation emerge. September tends to be milder, with average temperatures around 7°C (45°F), while April averages at a colder 0°C (33°F). This is reflected in the minimum temperatures, where April can drop as low as -19°C (-1°F), compared to September’s minimum of -8°C (17°F). Additionally, September experiences significantly more precipitation, with 127 mm (5.0 in) falling over 18 days, whereas April has only 54 mm (2.1 in) over 10 days. The humidity also plays a role, with September being more humid at 96% compared to April's 85%. For more detailed insights, you can check Knik River weather in April.

When comparing the weather in September and May, one can observe a slight difference in temperature. September typically experiences a minimum temperature of -8°C (17°F) and an average temperature of 7°C (45°F), peaking at 18°C (65°F). In contrast, May has slightly milder temperatures, with a minimum of -6°C (21°F), an average of 5°C (42°F), and a maximum reaching 19°C (66°F). Regarding precipitation, September sees significantly more rainfall at 127 mm (5.0 in) over 18 days, compared to May’s 75 mm (2.9 in) across 14 days. Additionally, September's humidity is higher at 96%, while May has a more comfortable 88%. For a detailed look at May weather in this region, check out Knik River weather in May.

September and June exhibit distinctive weather patterns, reflecting the transition from late summer to early fall. In June, temperatures range from a minimum of 0°C (32°F) to a maximum of 25°C (77°F), with an average of 11°C (51°F), making it a warmer month overall. September, on the other hand, sees cooler temperatures, with a minimum of -8°C (17°F) and a maximum of 18°C (65°F), averaging just 7°C (45°F). Precipitation is more frequent in September, amounting to 127 mm (5.0 in) over 18 days, compared to June's 83 mm (3.3 in) over 20 days. The humidity levels are similarly high, although September is slightly more humid at 96% versus June's 95%. For more details on the weather in June, you can check this link: Knik River weather in June.

In comparing the weather between September and July, noticeable differences emerge. September features cooler temperatures, with a minimum of -8°C (17°F) and an average of 7°C (45°F), while July boasts milder conditions, starting at a minimum of 5°C (41°F) and peaking at an average of 13°C (56°F). Additionally, July experiences warmer highs, reaching up to 26°C (79°F), compared to September's maximum of 18°C (65°F). Precipitation levels are higher in September, totaling 127 mm (5.0 in) over 18 days, while July sees 89 mm (3.5 in) across 16 days. Interestingly, the humidity levels also differ, with July slightly higher at 102%, compared to September's 96%. For more detailed weather information, you can check Knik River weather in July.

In comparing the weather conditions of September and August, September experiences notably cooler temperatures, with averages ranging from a chilly minimum of -8°C (17°F) to a maximum of 18°C (65°F). In contrast, August boasts warmer averages, with minimum temperatures around 1°C (34°F) and maximums reaching up to 23°C (74°F). While both months are relatively wet, September sees a slight decrease in precipitation, recording 127 mm (5.0 in) over 18 days compared to August's 137 mm (5.4 in) over the same number of days. Furthermore, September's humidity remains high at 96%, slightly less than August's peak of 100%. For a detailed look at August's weather patterns, you can visit Knik River weather in August.

September tends to be milder than October, with average temperatures ranging from -8°C (17°F) at night to a comfortable 18°C (65°F) during the day, while October sees colder conditions, with temperatures dropping to a minimum of -15°C (6°F) and a maximum of 15°C (59°F). Additionally, September experiences slightly less precipitation with 127 mm (5.0 in) over 18 days, compared to October's 173 mm (6.8 in) across 19 days. Humidity levels remain high in both months, but September's 96% is marginally higher than October's 91%. For those curious about the specific weather in October, more details can be found here: Knik River weather in October.

September and November present stark contrasts in weather conditions. In September, temperatures range from a minimum of -8°C (17°F) to a maximum of 18°C (65°F), with an average temperature of 7°C (45°F). The month experiences considerable precipitation, totaling 127 mm (5.0 in) across 18 days, and high humidity levels of 96%. In contrast, November sees a significant drop in temperatures, with a minimum of -33°C (-27°F), an average of -9°C (17°F), and a maximum of only 4°C (39°F). While precipitation decreases slightly to 114 mm (4.5 in) over 13 days, humidity remains high at 95%. For more detailed insights into this month's climate, check out Knik River weather in November.

In September, the weather is relatively mild with temperatures ranging from a minimum of -8°C (17°F) to a maximum of 18°C (65°F) and an average of 7°C (45°F). The month sees approximately 127 mm (5.0 in) of precipitation over 18 days, accompanied by high humidity levels at 96%. In contrast, December brings significantly colder temperatures, with a minimum of -26°C (-14°F) and a maximum of 6°C (42°F), resulting in an average of -8°C (17°F). Precipitation slightly increases to 142 mm (5.6 in) over 19 days, while humidity remains constant at 96%. For more detailed information, you can check Knik River weather in December.

Compare Knik River's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Knik River

As September rolls into the Knik River area, the weather undergoes a distinct transformation compared to the preceding summer months. With temperatures cooling down significantly, the vibrancy of autumn begins to take hold, making this a picturesque time for visitors and locals alike. In contrast to the warm, dry days of summer, September brings increased humidity and frequent rainfall, creating a misty, enchanting backdrop. The combination of cooler temperatures and abundant precipitation contributes to a more textured and colorful landscape. For those eager to experience the unique shift in Knik River's climate, more details can be found at Knik River Climate.