September Weather in Big Bear City, United States

Last updated: February 24, 2025

In September, Big Bear City experiences a delightful mix of warm and cool weather, with maximum temperatures soaring up to 37°C (99°F), while the average temperature settles around 21°C (71°F). The nights bring a refreshing coolness, with minimum temperatures dipping to 6°C (43°F). Although the month sees only 13 mm (0.5 in) of precipitation over a mere 2 days, the overall humidity sits comfortably at 41%, making for pleasant outdoor conditions. This blend of warmth and coolness makes September an ideal time to enjoy the scenic beauty and recreational activities that Big Bear City has to offer.

September Temperature in Big Bear City

September in Big Bear City ushers in a transition from the summer heat to the crisp beginnings of autumn. With minimum temperatures averaging 6°C (43°F) and a pleasant average of 21°C (71°F), the month strikes a balance that invites outdoor adventures. The maximum highs, reaching up to 37°C (99°F), can still be quite warm, offering lingering summer-like days. As nature prepares to don its fall colors, September's mild climate provides the perfect backdrop for exploring the breathtaking landscapes before cooler temperatures set in. This month embodies a harmonious blend of warmth and the gentle onset of autumn's embrace, making it an ideal time for both relaxation and exploration.

September Weather in Big Bear City: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Big Bear City, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec434347566172777670605243
Data source: Temperature data for Big Bear City 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 Big Bear City

September in Big Bear City marks a subtle transition toward autumn, characterized by lower precipitation levels. With just 13 mm (0.5 inches) of rainfall spread across an average of 2 days, the month signifies a noticeable decline compared to the summer months, which typically see heftier rainfalls. This shift continues the pattern observed throughout the year, with September registering one of the lowest amounts of precipitation, following the drier summer months of June and May. As the landscape prepares for the cooler months ahead, the decrease in rain paves the way for vibrant fall foliage and gradually cooler temperatures, inviting nature enthusiasts and tourists alike to enjoy the serene beauty of the changing season.

September Precipitation Trends in Big Bear City

The chart displays monthly precipitation patterns in Big Bear City, 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.
JanFebMarAprMayJunJulAugSepOctNovDec44484423207472814101644
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Big Bear City

In Big Bear City, September marks a notable shift in humidity, with levels rising to 41% after the summer's drier months, where humidity dipped to as low as 28% in August. This increase signals the transition to autumn, contrasting sharply with the peak dryness seen in July and August. As the temperatures begin to cool, the humidity levels gradually climb, foreshadowing the damp conditions of fall and winter. This seasonal progression highlights the dynamic nature of Big Bear City's climate, with early September standing as a gentle reminder of the lush moisture that will soon envelop the region as the year winds down.

September Average Humidity in Big Bear City

This chart illustrates the average monthly humidity levels in Big Bear City, 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.
JanFebMarAprMayJunJulAugSepOctNovDec76%80%69%57%45%34%29%28%42%54%68%75%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Big Bear City

In September at Big Bear City, the UV index remains high, reflecting continuing exposure to the sun's rays with an index value of 11 categorized as extreme. This trend signifies a consistent pattern throughout the summer months where high UV levels in July and August peak at 13 and 11, respectively. As the season transitions into autumn, sun protection remains essential, as individuals can still experience a quick burn time of just 10 minutes. It’s a reminder to stay vigilant against overexposure, as the remaining fall months see a gradual decline in UV intensity. For those planning outdoor activities, understanding the UV index is crucial; for more detailed information, check Big Bear City UV Index.

Maximum UV Index Levels in Big Bear City for September

The chart shows the monthly maximum UV Index (UVI) for Big Bear City 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.
JanFebMarAprMayJunJulAugSepOctNovDec479111212131111864
Data source: Big Bear City 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 Big Bear City

In Big Bear City, September welcomes a delightful embrace of sunshine, totaling 324 hours of bright skies and radiant days. This month signifies a gentle transition from the sun-drenched heights of summer, which peaks in July at 383 hours. As the warm days of late summer gradually give way to the crispness of autumn, September's sunshine remains abundant, notably higher than October's 301 hours and November's 261 hours. This pattern underscores a trend where the summer months consistently bask in the most sunlight, creating a perfect backdrop for outdoor adventures and leisurely strolls in the scenic beauty of the mountains. With October on the horizon, September serves as a brilliant farewell to the summer warmth, inviting locals and visitors alike to savor every last ray of sunshine.

Monthly Sunshine Duration in Big Bear City: September Highlighted

The September sunshine duration represents the total number of hours Big Bear City 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.
JanFebMarAprMayJunJulAugSepOctNovDec194h249h301h330h373h381h383h363h324h301h261h233h
Data source: Big Bear City September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Big Bear City During September

September in Big Bear City shines brightly as one of the most sun-drenched months of the year, boasting a remarkable 86% chance of sunny weather. This trend of increasing sunshine is evident as the summer months unfold, with July hitting a low at 50%, but the outlook significantly brightens in August and maintains its brilliance into September. The transition from summer to early autumn witnesses not only warm temperatures but also an invigorating abundance of sunshine, making this month an ideal time for outdoor activities and soaking in the natural beauty of the area. Following September, the likelihood of sunny days begins to dip into the fall months, emphasizing the importance of seizing the sun-drenched days while they last.

Percentage of Sunny Days in September in Big Bear City

The chart illustrates the percentage of sunny days in Big Bear City 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 Big Bear City experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec59%72%70%73%86%66%50%79%86%73%76%51%
Data source: Big Bear City September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Big Bear City in September

As summer fades into autumn in Big Bear City, the month of September brings a gentle transition in daylight hours, offering 12 hours of sunlight. This notable reduction from the longer 14 hours experienced during the peak summer months of June and July signals the upcoming seasonal shift. Following a gradual increase in daylight from 10 hours in January to a peak in June, September marks the beginning of a slow decline as we approach October, which sees 11 hours of daylight. This pattern reflects a natural rhythm, where the vibrant summer days begin to give way to the coziness of fall, inviting locals and visitors alike to relish the crisp air and changing leaves against the backdrop of a beautifully sunlit landscape.

Average Daylight Hours in Big Bear City for September

The chart illustrates the variation in daylight duration in Big Bear City throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 8m10h 57m11h 59m13h 3m13h 57m14h 23m14h 9m13h 21m12h 20m11h 16m10h 21m9h 53m
Data source: Big Bear City daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Big Bear City

In September, Big Bear City experiences a gentle reprieve in wind speed, averaging around 2.2 m/s (5 mph). This slight decrease follows a gradual rise in windy conditions from the earlier months, with April peaking at 2.9 m/s (7 mph). As summer transitions to fall, the wind remains consistent, mirroring the calm before the winter months set in. Overall, September's breezy yet mild atmosphere complements the stunning landscape, inviting outdoor enthusiasts to enjoy the crisp mountain air while taking in the vibrant changes of the season. This pattern suggests a serene shift as the year begins to wind down, leading to the cozy, quieter months ahead.

Average September Wind Speed in Big Bear City

The chart displays monthly wind speed patterns in Big Bear City, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.32.62.82.92.72.42.02.12.2 m/s2.22.02.2
Data source: Big Bear City September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Big Bear City Compares to Other Months

The weather in Big Bear City 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 Big Bear City and find detailed weather information for every month.

September and January present stark contrasts in weather patterns. In September, temperatures range from a mild minimum of 6°C (43°F) to a scorching maximum of 37°C (99°F), with an average temperature of 21°C (71°F). The month sees minimal rainfall, only 13 mm (0.5 in) over just 2 days, accompanied by relatively low humidity at 41%. In contrast, January experiences much colder temperatures, with a minimum of -9°C (15°F) and an average of 6°C (43°F), peaking at a maximum of 21°C (69°F). This winter month is characterized by higher precipitation, totaling 44 mm (1.7 in) across 5 days, and significantly increased humidity at 76%. For more details, you can refer to Big Bear City weather in January.

September and February present a striking contrast in weather patterns. In September, temperatures range from a pleasant 6°C (43°F) at night to a warm 37°C (99°F) during the day, with an average of 21°C (71°F). The month sees minimal precipitation, totaling just 13 mm (0.5 in) over only 2 days, and humidity levels are relatively low at 41%.

In contrast, February experiences much colder temperatures, with a minimum of -10°C (15°F) and a maximum of 21°C (70°F), averaging around 6°C (43°F). This month is wetter, with 48 mm (1.9 in) of precipitation over 6 days, and the humidity is significantly higher at 80%. For more detailed information, visit Big Bear City weather in February.

When comparing the weather conditions of September and March, it’s evident that September enjoys notably warmer temperatures, with averages around 21°C (71°F) and maximums reaching up to 37°C (99°F). In contrast, March experiences much cooler temperatures, averaging only 8°C (47°F) and dipping as low as -7°C (20°F). Additionally, September is relatively dry, with only 13 mm (0.5 in) of precipitation over just 2 days, while March is much wetter, receiving 44 mm (1.7 in) across 7 days of precipitation. The humidity in September is also lower at 41%, compared to a higher 69% in March, indicating a more comfortable feel in the latter part of the year. For more details, check out the link: Big Bear City weather in March.

When comparing the weather in September and April, we see distinct differences in temperature and humidity. September tends to be much warmer, with average temperatures soaring to 21°C (71°F) and a maximum of 37°C (99°F), while April has a cooler average of 13°C (56°F) and peaks at 29°C (84°F). Additionally, September's lower humidity at 41% makes it feel drier, whereas April can feel more damp with 57% humidity. Precipitation is also notable; April experiences more rainfall, with 23 mm (0.9 in) over 2 days compared to September's lighter 13 mm (0.5 in) over the same number of days. For more specific details, you can check Big Bear City weather in April.

When comparing the weather in September to that in May, notable differences become apparent. September typically boasts a milder minimum temperature of 6°C (43°F) and can reach a warm maximum of 37°C (99°F), with an average temperature of 21°C (71°F). In contrast, May starts off cooler, with a minimum temperature of 0°C (32°F) and averages around 16°C (61°F), peaking at 34°C (93°F). Additionally, September experiences less rainfall, with only 13 mm (0.5 in) over 2 days, compared to May's 20 mm (0.8 in) across 3 days. Humidity levels are also slightly lower in September at 41%, while May sees a humidity of 45%. For more detailed insights, check Big Bear City weather in May.

In comparing the weather between September and June, we find that both months experience similar temperature extremes, with minimums at 6°C (43°F) and maximums reaching up to 37°C (99°F). However, September boasts a slightly higher average temperature of 21°C (71°F) compared to June's average of 22°C (72°F). Precipitation is more prevalent in September, with 13 mm (0.5 in) over 2 days, while June sees just 7 mm (0.3 in) over 1 day, resulting in lower humidity in June at 34% compared to September's 41%. For more detailed information, check out Big Bear City weather in June.

In comparing the weather of September and July, September presents a wider range of temperatures with a minimum of 6°C (43°F) and a maximum soaring to 37°C (99°F), averaging around 21°C (71°F). In contrast, July tends to be warmer overall, with minimum temperatures at 11°C (51°F), an average of 25°C (77°F), and a maximum reaching 38°C (101°F). Additionally, September experiences much lower precipitation at just 13 mm (0.5 in) over 2 days, while July sees significantly higher rainfall, totaling 47 mm (1.9 in) across 8 days. Humidity levels also differ, with September at 41% compared to July's more comfortable 29%. For more detailed information, you can check the Big Bear City weather in July.

In comparison to August, September experiences cooler temperatures overall, with an average of 21°C (71°F) compared to August's 25°C (77°F). September also sees a more significant temperature fluctuation, with a minimum temperature dropping to 6°C (43°F) while still reaching a maximum of 37°C (99°F). Precipitation amounts are lower in September, with only 13 mm (0.5 in) over 2 days, while August has 28 mm (1.1 in) spread across 6 days. Additionally, September is slightly more humid, with levels around 41% compared to August's 28%. For more detailed weather insights, check out Big Bear City weather in August.

September typically boasts warmer temperatures, with averages reaching around 21°C (71°F) and highs soaring up to 37°C (99°F), while October sees a noticeable drop, with an average temperature of 15°C (60°F) and maximums peaking at 31°C (88°F). Precipitation remains low in both months, with September recording 13 mm (0.5 in) over 2 days and October slightly less at 10 mm (0.4 in), but October experiences higher humidity at 54% compared to September’s 41%. For a detailed look at October weather, you can visit Big Bear City weather in October.

September and November present striking contrasts in weather conditions. In September, temperatures range from a mild minimum of 6°C (43°F) to a scorching maximum of 37°C (99°F), with an average of 21°C (71°F). The month sees minimal precipitation at just 13 mm (0.5 in) over two days and a relatively low humidity of 41%. In contrast, November introduces cooler temperatures, featuring a minimum of -6°C (22°F) and a maximum of 25°C (77°F), with an average of 11°C (52°F). Precipitation increases slightly to 16 mm (0.6 in), but it still occurs over the same two days. Additionally, humidity rises significantly to 68%, creating a much wetter feel. For more details on the weather specifics, you can check Big Bear City weather in November.

In September, temperatures in Big Bear City are much warmer, ranging from a low of 6°C (43°F) to a high of 37°C (99°F) with an average of 21°C (71°F). The month sees minimal precipitation, only 13 mm (0.5 in) over just two days, and the humidity level is relatively low at 41%. In contrast, December brings a significant drop in temperatures, with lows plummeting to -9°C (15°F) and an average of just 6°C (44°F), and a maximum of 20°C (69°F). This month also experiences higher precipitation, totaling 44 mm (1.7 in) across five days, and much higher humidity at 75%. For more insights on December weather, you can visit Big Bear City weather in December.

Compare Big Bear City's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Big Bear City

As summer transitions into fall, September in Big Bear City brings a delightful change in weather dynamics, offering a refreshing escape from the sweltering heat of the preceding months. With temperatures enjoying a comfortable average, mornings cool down significantly, inviting outdoor enthusiasts to explore the stunning landscapes without the intense summer sun. Rainfall remains modest, often gracing the region with just a couple of drizzly days, while humidity is pleasantly low, making it an ideal time for hiking and other adventures. For more insights into the climatic shifts throughout the year, check out Big Bear City Climate.