September Weather in Imperial Beach, United States

Last updated: February 24, 2025

September in Imperial Beach, United States offers a delightful coastal experience characterized by warm, inviting temperatures. With a maximum of 30°C (86°F) and an average of 21°C (70°F), the weather is perfect for enjoying the beach, while the minimum temperature dips to a pleasant 16°C (61°F) at night. This month boasts a remarkably dry climate, recording only 6 mm (0.2 in) of rain over 0 days, allowing for uninterrupted outdoor activities. Additionally, the average humidity sits at a comfortable 52%, making it an ideal time for both relaxation and adventure along the stunning shores of Imperial Beach.

September Temperature in Imperial Beach

In September, Imperial Beach enjoys a delightful embrace of warm temperatures as summer winds down. With minimums of 16°C (61°F) and average highs peaking at 30°C (86°F), this coastal gem offers a perfect blend of warmth and comfort. It's a month where the ocean invites long beach days, and the evenings are pleasantly mild, maintaining an average temperature of 21°C (70°F). This trend of rising warmth from the earlier months peaks here, just before the seasonal shift in October, making September an ideal time for outdoor activities and soaking in the sun before fall sets in.

September Weather in Imperial Beach: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Imperial Beach, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec575657606164697169676257
Data source: Temperature data for Imperial Beach 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 Imperial Beach

In September, Imperial Beach experiences a significant decline in precipitation, with a mere 6 mm (0.2 in) recorded across the month and no rainy days to speak of. This marks a continuation of the dry spell that begins in late spring and stretches through the summer, where barely any rainfall is noted in June, July, and August. As the region transitions into autumn, September seems to maintain this trend of minimal moisture, serving as a precursor to a somewhat wetter October. Overall, the month stands out as one of the driest periods in the yearly cycle, reflecting a characteristic aspect of the coastal climate in this vibrant beach town.

September Precipitation Trends in Imperial Beach

The chart displays monthly precipitation patterns in Imperial Beach, 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.
JanFebMarAprMayJunJulAugSepOctNovDec60755727267556143568
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Imperial Beach

As summer fades, September in Imperial Beach brings a noticeable shift in humidity levels, settling at 52%—a modest increase from the drier months of July and August, which hovered around 46% and 42% respectively. This slight uptick signals the transition towards autumn, contrasting with the early year's higher humidity, especially in February when it reached a peak of 77%. The general trend reveals that as the year unfolds, the coastal community experiences a gradual reduction in moisture during the warmer months, followed by a mild rise as the cooler months approach. The refreshing conditions in September make it an ideal time to enjoy the beach before the chill of fall sets in.

September Average Humidity in Imperial Beach

This chart illustrates the average monthly humidity levels in Imperial Beach, 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 Imperial Beach

As September rolls into Imperial Beach, the sun continues to shine with a UV Index of 10, classified as very high. This marks a slight decrease from the peak intensity experienced during the summer months, yet it still demands caution for sunbathers and outdoor enthusiasts alike. With a burn time of just 15 minutes, it's crucial to seek shade or apply sunscreen to protect your skin. This trend of high UV exposure persists from late spring through early fall, highlighting the need for sun safety during these months. As we transition into October, the UV Index begins to decline, inviting a shift to more moderate exposure. For more detailed insights, check out the Imperial Beach UV Index.

Maximum UV Index Levels in Imperial Beach for September

The chart shows the monthly maximum UV Index (UVI) for Imperial Beach 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.
JanFebMarAprMayJunJulAugSepOctNovDec468101111111110754
Data source: Imperial Beach 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 Imperial Beach

As summer draws to a close, September in Imperial Beach continues to bask in abundant sunshine, boasting 318 hours of glorious daylight. This trend marks a gradual decline from the peak sunlit hours in July, yet it remains significantly higher than the earlier months of the year. Throughout the summer, the region enjoys its brightest days, with July shining the brightest at 375 hours, followed closely by June and August. The transition into fall brings a slight dimming, yet September still retains warmth and light as it delicately bridges the vibrant summer to the cooler autumn months. This enduring sunshine makes Imperial Beach a favored destination for those seeking to soak in the last rays of summer before the days shorten further.

Monthly Sunshine Duration in Imperial Beach: September Highlighted

The September sunshine duration represents the total number of hours Imperial Beach 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.
JanFebMarAprMayJunJulAugSepOctNovDec196h243h299h324h359h364h375h360h318h298h258h236h
Data source: Imperial Beach September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Imperial Beach During September

September shines as one of the sunniest months in Imperial Beach, boasting a 67% chance of sunny weather. This slight increase from the summer months reflects a positive trend as the coastal area transitions from the heat of August, which also enjoys a solid 63% sunshine probability. In fact, September stands out among the other months, offering an inviting atmosphere for beachgoers and outdoor enthusiasts alike, with only October and November following closely behind at 64% and 63% respectively. As the year progresses into autumn, the likelihood of clear skies remains relatively high, making September an ideal time to soak in the sun and enjoy the beachside charm of this picturesque destination.

Percentage of Sunny Days in September in Imperial Beach

The chart illustrates the percentage of sunny days in Imperial Beach 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 Imperial Beach experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec63%61%61%51%49%49%53%63%67%64%63%45%
Data source: Imperial Beach September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Imperial Beach in September

As summer draws to a close in September, Imperial Beach enjoys a sunny farewell with an average of 12 hours of daylight. This marks a gentle decline from the peak of 14 hours in both June and July, reflecting the natural transition into autumn. Following the warm months, September's balance of light hints at the approaching season change, where daylight gradually wanes, leading into October's 11 hours. The trend showcases a rhythmic ebb and flow throughout the year, offering residents and visitors alike a perfect backdrop of sun-kissed days before the shorter daylight hours set in during the winter months.

Average Daylight Hours in Imperial Beach for September

The chart illustrates the variation in daylight duration in Imperial Beach throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 16m11h 1m12h13h13h 50m14h 14m14h 1m13h 16m12h 19m11h 19m10h 27m10h 2m
Data source: Imperial Beach daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Imperial Beach

In September, Imperial Beach experiences a gentle average wind speed of 2.9 m/s (7 mph), consistent with the breezy conditions of the summer months. This stability marks a notable trend in the wind patterns, as the speeds have remained relatively steady from July onwards. While the wind is slightly lower than the peak speeds found in the earlier spring months, it continues to provide a refreshing touch to warm coastal days. As the year transitions into autumn, the wind's reliability remains a hallmark of Imperial Beach, creating an inviting atmosphere for beachgoers and outdoor enthusiasts alike.

Average September Wind Speed in Imperial Beach

The chart displays monthly wind speed patterns in Imperial Beach, 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.
JanFebMarAprMayJunJulAugSepOctNovDec3.22.73.33.12.93.12.92.92.9 m/s2.82.53.1
Data source: Imperial Beach September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Imperial Beach Compares to Other Months

The weather in Imperial Beach 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 Imperial Beach and find detailed weather information for every month.

September and January present markedly different weather patterns. In September, temperatures range from a comfortable minimum of 16°C (61°F) to a warm maximum of 30°C (86°F), with an average of 21°C (70°F). The month is quite dry, receiving only 6 mm (0.2 in) of precipitation over no days, and has a moderate humidity level of 52%. In contrast, January features significantly cooler temperatures, with a minimum of 7°C (45°F), an average of 14°C (57°F), and a maximum reaching 23°C (75°F). This month experiences more rainfall, accumulating 60 mm (2.3 in) over six days, along with a higher humidity of 72%. For a more detailed look at January weather, visit Imperial Beach weather in January.

September and February present quite contrasting weather patterns. In September, temperatures range from a mild 16°C (61°F) to a warm 30°C (86°F), with low humidity at 52% and virtually no precipitation. In sharp contrast, February sees cooler temperatures, with lows of 6°C (43°F) and highs of 25°C (77°F), along with significantly higher humidity at 77% and substantial rainfall, averaging 75 mm (3.0 in) over about 7 days. This highlights a clear shift from the drier, warmer conditions of late summer to the cooler and wetter climate typical of mid-winter. For more information about February weather specifically, you can check Imperial Beach weather in February.

September's weather boasts warmer temperatures, with a minimum of 16°C (61°F) and a comfortable average of 21°C (70°F), peaking at a maximum of 30°C (86°F). The month is relatively dry, receiving only 6 mm (0.2 in) of precipitation and experiencing no rainy days, while humidity hovers around 52%.

In contrast, March features much cooler conditions, with temperatures ranging from a low of 7°C (45°F) to an average of 14°C (57°F), and a maximum of 24°C (76°F). This month is significantly wetter, accumulating 57 mm (2.2 in) of precipitation over 10 days, accompanied by a higher humidity level of 67%.

For more details on weather patterns, you can check Imperial Beach weather in March.

When comparing the weather in September and April, it's evident that September tends to be warmer and drier. In September, temperatures typically range from a minimum of 16°C (61°F) to a maximum of 30°C (86°F), with an average of 21°C (70°F) and virtually no precipitation. In contrast, April generally features cooler temperatures, with a minimum of 10°C (51°F) and a maximum of 27°C (81°F), resulting in an average of 15°C (60°F). Moreover, April experiences more humidity at 56% and an average precipitation of 27 mm (1.1 in) over about four days, indicating a wetter month. For more detailed information about the weather in April, you can visit Imperial Beach weather in April.

September weather is generally warmer than May, with temperatures ranging from a minimum of 16°C (61°F) to a maximum of 30°C (86°F) and an average of 21°C (70°F). In contrast, May has cooler temperatures, with lows of 11°C (52°F) and highs of 24°C (76°F), averaging around 16°C (61°F). Additionally, September boasts lower precipitation, with only about 6 mm (0.2 in) over no days of rain, while May experiences more rainfall at 26 mm (1.0 in) across six days. Humidity levels are slightly higher in September at 52%, compared to 46% in May. For more details on May weather patterns, you can visit Imperial Beach weather in May.

September generally offers warmer temperatures compared to June, with averages reaching up to 21°C (70°F) and maximums of 30°C (86°F), while June's averages are slightly cooler at 18°C (65°F) with max temperatures at 27°C (80°F). Both months have minimal precipitation, with September experiencing only 6 mm (0.2 in) and June slightly higher at 7 mm (0.3 in), yet neither month sees significant rain. Humidity levels in September are slightly higher at 52%, compared to June's 48%, making September feel a bit warmer and more humid. For a detailed look at June weather conditions, you can visit Imperial Beach weather in June.

Comparing the weather in September and July reveals subtle differences. Both months experience similar minimum temperatures, with September slightly warmer at a minimum of 16°C (61°F) compared to July's 16°C (60°F). The average temperature remains consistent, with September averaging 21°C (70°F) and July at 21°C (69°F). However, September boasts a higher maximum temperature of 30°C (86°F), while July reaches a comfortable 28°C (83°F). Precipitation levels are comparable in both months, with September receiving 6 mm (0.2 in) and July slightly less at 5 mm (0.2 in), with no rainy days reported for either month. Humidity is slightly higher in September at 52%, compared to 46% in July, making September feel a bit more humid overall. For more detailed information, you can check Imperial Beach weather in July.

In comparing the weather between September and August, we find that September has a slightly warmer temperature range with a minimum of 16°C (61°F) and a maximum of 30°C (86°F), whereas August starts off a bit warmer with a minimum of 17°C (62°F) and a maximum of 28°C (83°F). Both months have a similar average temperature of 21°C (70°F), but September enjoys marginally less precipitation, totaling 6 mm (0.2 in) with no rainy days, compared to August's 5 mm (0.2 in) also with no rainy days. Additionally, September exhibits higher humidity at 52%, while August maintains a lower humidity level of 42%. For more details on August weather, you can check out Imperial Beach weather in August.

In comparing the weather between September and October, September tends to be slightly warmer, with average temperatures reaching up to 21°C (70°F) and a maximum of 30°C (86°F), while October sees a decrease in average temperature to 19°C (67°F), despite a higher maximum of 32°C (90°F). Precipitation also increases in October, with 14 mm (0.6 in) recorded over 2 days, whereas September remained dry with no precipitation. Additionally, humidity levels are higher in October at 58% compared to 52% in September, indicating a shift towards a more humid climate as autumn progresses. For those interested in specific conditions, you can check the detailed weather for October Imperial Beach weather in October.

In September, the weather is generally warmer, with temperatures ranging from a minimum of 16°C (61°F) to a maximum of 30°C (86°F) and an average of 21°C (70°F). The humidity is lower at 52%, and there is little to no precipitation, making it a dry month. In contrast, November sees cooler temperatures, with a minimum of 9°C (49°F) and a maximum of 27°C (80°F), along with an average of 17°C (62°F). Precipitation increases significantly to 35 mm (1.4 in) across two days, and humidity also rises to 66%. For more insights into the November weather, visit Imperial Beach weather in November.

September and December present contrasting weather conditions. In September, temperatures range from a mild 16°C (61°F) at night to a warm 30°C (86°F) during the day, with an average of 21°C (70°F) and very little precipitation, receiving only 6 mm (0.2 in) over 0 days. The humidity is relatively moderate at 52%. In sharp contrast, December experiences cooler temperatures, with a minimum of 8°C (46°F) and a maximum of 23°C (73°F), averaging 14°C (58°F). This month receives significantly more rainfall, totaling 68 mm (2.7 in) across 6 days, and the humidity increases to 74%. For more details about the December climate, you can check Imperial Beach weather in December.

Compare Imperial Beach's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Imperial Beach

As summer gracefully transitions into fall, September in Imperial Beach offers a delightful reprieve from the sweltering heat. With warm maximum temperatures that reach a comfortable 30°C (86°F) and refreshing average lows of 16°C (61°F), it's a perfect time for beachgoers to soak in the sun without the oppressive humidity typical of other months. Impressively, the area enjoys dry conditions throughout the month, recording no precipitation, making it a prime time for outdoor activities. Whether you're lounging by the surf or exploring the scenic coastlines, the weather sets the stage for an unforgettable experience. For more insights on the distinctive climate patterns of Imperial Beach, visit Imperial Beach Climate.