September Weather in Idyllwild, United States

Last updated: February 24, 2025

In September, Idyllwild experiences a blend of warmth and coolness, with maximum temperatures soaring to 42°C (108°F) and an average of 23°C (74°F). The nights offer refreshing relief, dipping to a minimum of 7°C (44°F). Rain is sparse, with only 7 mm (0.3 in) of precipitation occurring across just 2 days, contributing to a moderate humidity level of 52%. This harmonious mix of temperatures and minimal rainfall makes September a delightful time to explore the natural beauty of Idyllwild.

September Temperature in Idyllwild

In Idyllwild, United States, September brings a noticeable shift in temperatures as summer begins its transition into fall. With minimum temperatures averaging around 7°C (44°F), the nights start to cool, offering a refreshing respite from the summer heat. The daytime, however, still clings to summer's warmth, with average highs reaching a sizzling 42°C (108°F), showcasing the tail end of the warm season. On average, temperatures settle around 23°C (74°F), reflecting a delightful balance that invites outdoor activities amidst the crisp air and vibrant autumn foliage. As September unfolds, Idyllwild's climate becomes a tapestry of warmth and gentle coolness, making it an enchanting time to experience the beauty of this mountain retreat.

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

The chart illustrates September temperature patterns in Idyllwild, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec484852596373797974645748
Data source: Temperature data for Idyllwild 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 Idyllwild

In September, Idyllwild experiences a significant drop in precipitation, with only 7 mm (0.3 in) recorded over just 2 days. This marks a continuation of the declining trend from the preceding summer months, where rainfall dwindles to a mere 11 mm (0.4 in) in August and an even lighter 19 mm (0.7 in) in July. As summer transitions into fall, this minimal rainfall highlights the area's characteristic dry spell, with precipitation levels reflecting the shifting seasons. Looking ahead, October promises a slight uptick with 14 mm (0.6 in) expected, but September stands as a testament to Idyllwild's arid late summer climate, providing a peaceful reprieve before the autumn rains prepare to return.

September Precipitation Trends in Idyllwild

The chart displays monthly precipitation patterns in Idyllwild, 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.
JanFebMarAprMayJunJulAugSepOctNovDec6470572514319117142558
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Idyllwild

In September, Idyllwild experiences a modest increase in humidity, averaging around 52%. This marks a shift from the drier months of summer, where humidity dipped to 42% in August. As the region transitions into fall, this rise signals a gradual return to the higher humidity levels characteristic of winter months, such as October at 58% and November at 66%. This trend reflects a seasonal pattern where humidity begins to creep back as temperatures cool, creating a more comfortable atmosphere that contrasts sharply with the dryness of mid-summer. Overall, September serves as a transitional month, bridging the gap between the aridness of summer and the increased moisture of the approaching autumn and winter seasons.

September Average Humidity in Idyllwild

This chart illustrates the average monthly humidity levels in Idyllwild, 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.
JanFebMarAprMayJunJulAugSepOctNovDec72%77%67%56%46%48%46%42%52%58%66%74%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Idyllwild

In September, Idyllwild experiences a notable shift in its UV Index, registering at 10 and falling into the very high exposure category. This marks a slight decline from the peak months of summer, where the UV Index reached a maximum of 12. With a burn time of just 15 minutes, sun protection remains vital as the days begin to cool down but still offer plenty of sunny outdoor activities. As the season transitions into autumn, September's UV levels are a reminder that while temperatures may drop, the sun's intensity can still pose risks, making it crucial for residents and visitors alike to stay vigilant about sun safety. For further insights into UV exposure trends throughout the year, check out Idyllwild UV Index.

Maximum UV Index Levels in Idyllwild for September

The chart shows the monthly maximum UV Index (UVI) for Idyllwild 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.
JanFebMarAprMayJunJulAugSepOctNovDec469111212121110854
Data source: Idyllwild 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 Idyllwild

September in Idyllwild is a delightful transition into fall, offering 322 hours of sunshine that beckon outdoor enthusiasts to explore the stunning landscape. As summer winds down, the sun-kissed days of July and August, which boast the highest sunshine hours at 381 and 363 respectively, begin to wane. However, the sunshine in September remains robust, highlighting a trend where late summer still delivers generous daylight. Meanwhile, the gradual decline leading into October, with its 301 hours, signals the annual shift towards shorter days ahead. This month beautifully balances the lingering warmth of summer with the crisp beginnings of autumn, making it an ideal time for hiking, apple picking, and basking in the glorious sun before winter approaches.

Monthly Sunshine Duration in Idyllwild: September Highlighted

The September sunshine duration represents the total number of hours Idyllwild 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.
JanFebMarAprMayJunJulAugSepOctNovDec194h250h302h331h373h377h381h363h322h301h260h231h
Data source: Idyllwild September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Idyllwild During September

In Idyllwild, United States, the month of September boasts a promising 85% chance of sunny weather, making it one of the sunniest months of the year. This notable increase follows a trend of rising sunshine, peaking after a summer filled with warmer days—a stark contrast to the chill of earlier months like December, which sees only 48% chance of sunshine. Notably, the late summer and early fall months demonstrate the region's inviting climate, with August leading the charge at 83%. After September, the likelihood gradually decreases, yet still remains relatively high through October at 70%. This trend underscores Idyllwild’s appeal for those seeking warm, sunny outdoor experiences in early autumn, inviting travelers and locals alike to soak up the sun before the cooler months set in.

Percentage of Sunny Days in September in Idyllwild

The chart illustrates the percentage of sunny days in Idyllwild 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 Idyllwild experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec59%67%61%67%77%70%59%83%85%70%76%48%
Data source: Idyllwild September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Idyllwild in September

As summer transitions to fall, September in Idyllwild, United States, showcases a gentle reduction in daylight, offering approximately 12 hours of sunlight each day. This decline follows a peak of 14 hours in June and July, gradually tapering off from the vibrant summer months, while still providing ample opportunities for outdoor activities. Following September, the days continue to shorten into October, where daylight dips to 11 hours. This gradual decrease signals the approach of autumn, marking a shift in both the scenery and the seasonal ambiance, while inviting a cozy embrace of the cooler evenings.

Average Daylight Hours in Idyllwild for September

The chart illustrates the variation in daylight duration in Idyllwild throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 11m10h 58m11h 59m13h 2m13h 55m14h 20m14h 6m13h 19m12h 19m11h 17m10h 23m9h 56m
Data source: Idyllwild daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Idyllwild

In Idyllwild, United States, September ushers in a gentle breeze with an average wind speed of 1.9 m/s (4 mph), slightly tapering off from the summer months. This subtle decrease mirrors the overall trend of diminishing wind speeds as the year progresses, as Idyllwild experiences its highest winds in April at 2.5 m/s (6 mph). The calming winds of September provide a serene backdrop to the stunning fall scenery, making it an ideal time for reflection and outdoor activities. As autumn sets in, locals and visitors alike can enjoy the tranquil atmosphere while anticipating the crisp, cool breezes that are characteristic of the season.

Average September Wind Speed in Idyllwild

The chart displays monthly wind speed patterns in Idyllwild, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.02.02.32.52.42.11.92.01.9 m/s2.01.81.9
Data source: Idyllwild September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Idyllwild Compares to Other Months

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

September and January present starkly contrasting weather conditions. In September, temperatures range from a minimum of 7°C (44°F) to a scorching maximum of 42°C (108°F), with an average of 23°C (74°F). This month sees minimal precipitation, totaling only 7 mm (0.3 in) over just two days, accompanied by a relatively comfortable humidity of 52%. In contrast, January features much cooler temperatures, with a minimum of -6°C (22°F), an average of 9°C (49°F), and a maximum of 26°C (79°F). The month is also significantly wetter, recording 64 mm (2.5 in) of precipitation across six days, and higher humidity levels at 72%. For those interested in specific weather patterns during this month, you can find more details here: Idyllwild weather in January.

September and February showcase starkly contrasting weather patterns. In September, the temperatures range from a brisk 7°C (44°F) at night to a sweltering peak of 42°C (108°F) during the day, with an average of 23°C (74°F). This month experiences minimal precipitation, totaling just 7 mm (0.3 in) over 2 days, making it relatively dry with a humidity level of 52%. In contrast, February brings much colder conditions, with temperatures dipping as low as -10°C (14°F) and only reaching a maximum of 26°C (78°F), averaging around 9°C (49°F). This winter month sees significantly more precipitation, with 70 mm (2.8 in) falling over 7 days and higher humidity at 77%. For a more detailed look at February weather in Idyllwild, you can refer to Idyllwild weather in February.

In September, the weather tends to be much warmer, with average temperatures around 23°C (74°F) and peaks reaching up to 42°C (108°F), accompanied by relatively low precipitation of only 7 mm (0.3 in) over 2 days. The humidity is also lower at 52%, making the heat more bearable. In contrast, March experiences cooler conditions, with average temperatures of 11°C (52°F) and a maximum of 29°C (85°F). This month sees significantly more rainfall, totaling 57 mm (2.3 in) over about 10 days, and higher humidity at 67%. For a closer look at the weather conditions in March, check out Idyllwild weather in March.

September and April exhibit contrasting weather patterns, reflecting the transition from summer to autumn and the onset of spring. In September, temperatures can soar to a high of 42°C (108°F) with a warm average of 23°C (74°F), while April's temperatures are notably cooler, peaking at 32°C (90°F) and averaging just 15°C (59°F). Additionally, September sees minimal precipitation at 7 mm (0.3 in) over just 2 days, whereas April experiences a higher rainfall of 25 mm (1.0 in) across 3 days. Humidity levels also vary slightly, with September at 52% and April at 56%. For more insights on April weather specifically, you can check out Idyllwild weather in April.

In September, temperatures in Idyllwild range from a minimum of 7°C (44°F) to a maximum of 42°C (108°F), with an average of 23°C (74°F). The month typically sees only 7 mm (0.3 in) of precipitation over just 2 days, contributing to a relatively dry atmosphere with humidity around 52%. In contrast, May features cooler weather, with temperatures ranging from a minimum of 3°C (37°F) to a maximum of 36°C (97°F) and an average of 17°C (63°F). Precipitation in May increases slightly to 13 mm (0.5 in), occurring over 3 days, and humidity is slightly lower at 46%. For more details on May's weather, visit Idyllwild weather in May.

In September, temperatures can range from a cool 7°C (44°F) at night up to a scorching maximum of 42°C (108°F) during the day, with an average temperature of 23°C (74°F). This month sees a bit more rain, with an average precipitation of 7 mm (0.3 in) over about 2 days, and humidity levels sitting around 52%. In contrast, June offers similar average temperatures of 23°C (73°F), but with a slightly higher minimum of 8°C (46°F) and a maximum of 39°C (103°F). Rain is uncommon in June, bringing only 3 mm (0.1 in) of precipitation across 0 days, and the humidity is a touch lower at 48%. For more specific details about June weather, you can visit Idyllwild weather in June.

In comparison to July, September experiences a wider temperature range, with a minimum of 7°C (44°F) and a maximum of 42°C (108°F), while July's temperatures range from a minimum of 11°C (52°F) to a maximum of 40°C (104°F). September also has significantly lower precipitation, averaging only 7 mm (0.3 in) over 2 days, compared to July's 19 mm (0.7 in) over 4 days. Additionally, September is slightly more humid at 52%, while July maintains a lower humidity level of 46%. For a detailed look at July weather in Idyllwild, you can explore this link: Idyllwild weather in July.

In comparison to August, September experiences a notable shift in weather patterns. The minimum temperature drops from 13°C (56°F) in August to 7°C (44°F) in September, indicating cooler nights. However, the average temperature decreases only slightly from 26°C (79°F) to 23°C (74°F), while the maximum temperature remains quite high, reaching up to 42°C (108°F) in September compared to 40°C (103°F) in August. Precipitation is also less frequent in September with only 7 mm (0.3 in) of rain over 2 days, whereas August sees a bit more rain, totaling 11 mm (0.4 in) over 3 days. Moreover, September’s humidity is higher at 52% compared to August's 42%. For a detailed look at August weather, check out Idyllwild weather in August.

September shows a warmer profile with average temperatures reaching up to 23°C (74°F) and maximums soaring to 42°C (108°F), while October experiences cooler conditions, averaging just 18°C (64°F) and peaking at 36°C (98°F). Precipitation increases in October, accumulating to 14 mm (0.6 in) over three days compared to September's 7 mm (0.3 in) over just two days. Humidity also rises slightly from 52% in September to 58% in October, indicating a shift towards a more moist atmosphere as the fall season progresses. For more detailed information, check out Idyllwild weather in October.

September and November present notably different weather patterns. In September, temperatures range from a comfortable minimum of 7°C (44°F) to a scorching maximum of 42°C (108°F), with an average of 23°C (74°F). The month is relatively dry, receiving only 7 mm (0.3 in) of precipitation over just two days and a humidity level of 52%. In contrast, November experiences much cooler temperatures, with a minimum of 0°C (32°F), an average of 14°C (57°F), and a maximum reaching 29°C (85°F). The month is also wetter, with 25 mm (1.0 in) of precipitation over the same two days, and humidity rises to 66%. For a detailed look at weather conditions specific to this month, check out Idyllwild weather in November.

In September, temperatures are warm and range from a chilly 7°C (44°F) at night to a scorching 42°C (108°F) during the day, with an average of 23°C (74°F). The month experiences minimal precipitation, with only 7 mm (0.3 inches) over just two days, and the humidity tends to be relatively low at 52%. In contrast, December brings much cooler weather, with temperatures dipping down to -5°C (23°F) at night and averaging around 9°C (49°F) during the day, peaking at 25°C (77°F). December also sees a significant increase in precipitation to 58 mm (2.3 inches) spread across five days, and the humidity rises to 74%. For a more detailed look, you can check Idyllwild weather in December.

Compare Idyllwild's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Idyllwild

September in Idyllwild marks a delightful transition from the heat of summer, featuring milder temperatures and significantly less precipitation compared to the earlier months. As the season shifts, average highs settle at a comfortable 23°C (74°F), offering a reprieve from the extreme summer heat. With only 2 days of light rainfall throughout the month, outdoor enthusiasts can relish in the abundance of sunshine amidst a subtly refreshing 52% humidity. This month is ideal for those seeking to enjoy the scenic landscapes and outdoor activities, all while experiencing the gentle onset of autumn. For a deeper dive into the nuances of Idyllwild's weather patterns, check out Idyllwild Climate.