Last updated: February 24, 2025
Experience Carlsbad's September climate, where temperatures reach a sizzling maximum of 40°C (104°F) and settle at a pleasant average of 23°C (73°F). With a minimum low of 13°C (55°F), the weather is ideal for those who enjoy warm days and cooler nights. Rain is a rare guest this month, with only 5 mm (0.2 in) falling over the span of just one day. Coupled with a moderate humidity level of 52%, September in Carlsbad offers a delightful mix of warmth and comfort, perfect for outdoor adventures.
In September, Carlsbad experiences a warm transition towards autumn, with temperatures reflecting the tail end of summer's heat. The minimum temperature hovers around 13°C (55°F), while the average climbs to a comfortable 23°C (73°F), and it can peak at a sizzling 40°C (104°F). This month showcases a notable high, similar to what is seen in July and August, indicating that the warm weather is not completely relinquishing its hold. As the days slowly shorten, the pleasant evenings invite outdoor activities, making September a lovely time to enjoy the outdoors before the cooler months set in.
In September, Carlsbad experiences a slight uptick in precipitation, with 5 mm (0.2 in) of rainfall recorded over just one day. This marks a slow return to wetter conditions after a notably dry summer, where July and August saw virtually no rain. As the warm days begin to wane, the shift in September's weather hints at the upcoming seasonal changes that bring more consistent moisture to the region. Compared to the heavier rains typically seen in the earlier months of the year, September's precipitation is modest, contributing to the overall trend of diminishing rainfall as the city transitions from summer heat towards fall.
In September, Carlsbad experiences a slight uptick in humidity, with levels reaching 52%. This marks a notable transition from the drier months of summer, where humidity dipped to as low as 42% in August. As the coastal winds begin to shift with the onset of autumn, September's humidity reflects a blend of residual summer warmth and the approaching cooler fall air. This transitional humidity level aligns with a general trend of increasing moisture, as figures gradually rise from the summer lows, paving the way towards the wetter months ahead. Although September remains relatively comfortable, it serves as a reminder of the changing seasons in this picturesque coastal town.
In September, Carlsbad experiences a UV Index of 10, placing it in the very high exposure category, which means you're at risk of sunburn with just 15 minutes of unprotected exposure. This month marks a slight dip from the intense summer months of July and August, where UV levels peaked at 11 and 10, respectively. However, it’s crucial to remain vigilant, as the UV radiation is still strong enough to warrant protective measures. As we transition into fall, the UV Index will decrease further in October, but September reminds us that summer's sun can linger. For more detailed information, visit Carlsbad UV Index.
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As summer begins to fade, September in Carlsbad welcomes a delightful transition with 319 hours of sunshine, offering a perfect blend of warmth and comfort. This month showcases a slight decline from the peak summer months of July and June, which basked in 378 and 369 hours of sunlight, respectively. However, September still retains a generous amount of sun, outshining October and November, which record 296 and 256 hours. This month is a gentle reminder of the lingering sunshine before the cooler days of fall set in, making it an ideal time for outdoor activities and enjoying the beautiful coastal landscape.
September in Carlsbad, United States, marks a delightful transition into the fall season, with the sun making a prominent appearance 65% of the time. This figure not only stands out as the highest chance of sunshine since August’s 64%, but it's also part of a broader trend of relatively high sunlight across the late summer and early fall months. Following a gradual decline from May's 46%, the likelihood of sunny days increases significantly, peaking in September, before tapering off slightly into the cooler months. As the days remain warm and inviting, September is a fantastic time to soak up the sun in this picturesque coastal city.
As September unfolds in Carlsbad, the days begin to gently shorten, offering about 12 hours of daylight—a transition that signals the approach of autumn. Following the sun-drenched months of summer, when the city basked in 14 hours of daylight, September marks a subtle yet noticeable shift, as daylight hours gradually recede. This pattern is reflective of the larger seasonal rhythm, where daylight peaks in June and then gradually declines through the fall and winter months. The lingering warmth of late summer still graces the skies in September, creating a perfect blend of sunlight and cooler breezes, inviting residents to savor the outdoor beauty before the days grow shorter and the nights longer.
In Carlsbad, September marks a subtle shift in the wind, as the average speed drops to 1.8 m/s (4 mph), mirroring the calmness of the summer months. This gentle breeze provides a serene backdrop to the retreating warmth of late summer, contributing to the area's mild climate. Interestingly, September's wind speed is part of a noticeable trend, as the months leading to it—particularly July and August—also experience lower gusts. As the year progresses into October, a slight uptick in wind speed is observed, hinting at the dynamic changes that await in the autumn months. Overall, September in Carlsbad captures a tranquil essence, perfect for outdoor activities as summer transitions to fall.
The weather in Carlsbad 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 Carlsbad and find detailed weather information for every month.
September and January present stark contrasts in weather conditions. In September, temperatures range significantly, with a minimum of 13°C (55°F) and a maximum soaring to 40°C (104°F), creating a warm and dry atmosphere with only 5 mm of precipitation over the course of a single day. In contrast, January brings cooler temperatures, with a low of 4°C (40°F) and a maximum of 30°C (87°F), accompanied by increased precipitation totaling 70 mm (2.8 in) over five days, resulting in higher humidity at 72%. This shift from the dry heat of September to the cooler, wetter conditions of January highlights the seasonal transition experienced in the region. For more detailed information, check out Carlsbad weather in January.
September and February present contrasting weather patterns. In September, temperatures range from a mild 13°C (55°F) at their lowest to a scorching 40°C (104°F) at their peak, with an average of 23°C (73°F). The month experiences minimal precipitation, totaling just 5 mm (0.2 in) over a single day, accompanied by moderate humidity of 52%. In stark contrast, February features cooler temperatures, with a minimum of 3°C (37°F), an average of 13°C (56°F), and a maximum of 29°C (85°F). This month is significantly wetter, receiving 78 mm (3.1 in) of rainfall over six days, alongside higher humidity levels of 77%. For a closer look at February conditions, you can refer to Carlsbad weather in February.
September weather is generally warm, with temperatures ranging from a pleasant 13°C (55°F) at night to a scorching maximum of 40°C (104°F) during the day. The month sees minimal precipitation, averaging just 5 mm (0.2 in) over only one day, and maintains a moderate humidity level of 52%. In contrast, March presents much cooler conditions, with minimum temperatures dropping to 5°C (41°F) and a maximum of 28°C (83°F). This month experiences significantly higher rainfall, totaling 68 mm (2.7 in) over approximately ten days, and a higher humidity level of 67%. For more specific insights on March weather, you can refer to Carlsbad weather in March.
When comparing the weather in September and April, significant differences are evident. September boasts warmer temperatures, with a minimum of 13°C (55°F), averaging 23°C (73°F), and peaks reaching as high as 40°C (104°F). It experiences minimal precipitation, only 5 mm (0.2 in) over just 1 day, and a relatively low humidity level of 52%. In contrast, April presents cooler conditions, with a minimum of 8°C (46°F) and an average of 16°C (62°F), along with a maximum of 34°C (93°F). Precipitation in April is notably higher, at 32 mm (1.3 in) spread across 3 days, accompanied by a slightly higher humidity of 56%. For more detailed information, you can check Carlsbad weather in April.
When comparing the weather in September and May, it's clear that September tends to be much warmer. With average temperatures ranging from a minimum of 13°C (55°F) to a maximum of 40°C (104°F) and minimal precipitation of just 5 mm (0.2 in) over 1 day, September's climate is quite dry and hot, boasting a humidity level of 52%. In contrast, May experiences cooler temperatures with a minimum of 9°C (49°F) and a maximum of 30°C (87°F). This month sees more precipitation, totaling 24 mm (0.9 in) over 4 days, and a slightly lower humidity of 46%. For more detailed insights into the weather conditions specific to this month, you can visit Carlsbad weather in May.
In comparison to June, September experiences a broader temperature range, with minimums of 13°C (55°F) rising to maximums of 40°C (104°F), giving an average temperature of 23°C (73°F). June, on the other hand, has a milder climate with a minimum temperature of 12°C (54°F) and a maximum of 33°C (92°F), resulting in a cooler average of 20°C (68°F). Both months see minimal precipitation, with September recording 5 mm (0.2 in) over just one day, while June remains drier with only 3 mm (0.1 in) and no rainy days. Additionally, humidity levels are slightly higher in September at 52%, compared to 48% in June. For more detailed insights into June weather, you can visit Carlsbad weather in June.
When comparing the weather in September and July, we observe a few key similarities and differences. Both months share an average temperature of 23°C (73°F), with the maximum temperature reaching up to 40°C (104°F) in September and 40°C (105°F) in July. However, September has a slightly lower minimum temperature of 13°C (55°F), compared to July's minimum of 15°C (60°F). Rainfall is minimal in both months; September sees just 5 mm (0.2 in) of precipitation over 1 day, while July experiences slightly less at 4 mm (0.2 in) with no recorded rainy days. Humidity is also a bit higher in September at 52%, compared to 46% in July, making September feel slightly more humid overall. For a more detailed look at July's climate specifics, you can check Carlsbad weather in July.
In comparing the weather between August and September, we see some notable differences. September tends to be slightly warmer, with an average temperature of 23°C (73°F) and a maximum of 40°C (104°F), compared to August's average of 24°C (75°F) and max of 34°C (94°F). Interestingly, September also experiences a broader temperature range, with a minimum of 13°C (55°F) versus August's 16°C (62°F). Precipitation is minimal in both months, but September records a small amount of rain (5 mm) over one day, unlike August, which had no recorded precipitation. Humidity levels are also slightly higher in September at 52%, compared to 42% in August. For more detailed insights, you can check Carlsbad weather in August.
In September, the weather features a warm average temperature of 23°C (73°F), with daytime highs reaching up to 40°C (104°F) and only minimal precipitation of 5 mm (0.2 in) over just one day. In contrast, October sees a slight drop in average temperature to 20°C (69°F), with lower minimum temperatures at 8°C (47°F) and still high daytime temperatures around 39°C (103°F). Additionally, October experiences increased humidity at 58% and doubles the rainfall to 12 mm (0.5 in) over two days. For more detailed insights, you can visit Carlsbad weather in October.
September weather is significantly warmer than November, with average temperatures around 23°C (73°F) and highs reaching up to 40°C (104°F). In contrast, November experiences cooler temperatures, with an average of 17°C (63°F) and maximums of 33°C (92°F). Additionally, September is characterized by minimal precipitation, only about 5 mm over a single day, while November sees a notable increase in rainfall, totaling 34 mm over three days, which contributes to higher humidity levels of 66%. For more detailed information on November weather, you can visit Carlsbad weather in November.
In September, the weather is typically warm and dry, with average temperatures reaching around 23°C (73°F) and maximums soaring up to 40°C (104°F). With only about 5 mm (0.2 in) of precipitation over just one day, humidity remains relatively low at 52%. In contrast, December brings cooler temperatures, with averages dropping to 14°C (57°F) and maximums around 28°C (83°F). This month also experiences significantly more rain, accumulating approximately 70 mm (2.7 in) over six days, leading to higher humidity levels at 74%. For more detailed insights, you can check out Carlsbad weather in December.
As September rolls in, Carlsbad experiences a delightful transition in weather, moving away from the sweltering summer heat. While temperatures can peak at a scorching 40°C, the average settles at a comfortable 23°C, making it an ideal time for outdoor activities. With only a brief spell of rain contributing to minimal precipitation, the air maintains a pleasant 52% humidity, offering a refreshing respite. This month stands out for its mild conditions and low precipitation, setting it apart from the hotter, often more humid days of summer. For a deeper dive into what this charming coastal city has to offer year-round, visit Carlsbad Climate.