Last updated: April 22, 2025
In September, San Diego, Mexico, experiences a warm and humid climate, with maximum temperatures reaching up to 31°C (88°F), while the average temperature hovers around a comfortable 20°C (68°F). However, the month is marked by its frequent rainfall, totaling approximately 147 mm (5.8 in) over 17 days, resulting in a relative humidity of 81%. This mix of temperatures and precipitation creates a tropical atmosphere, ideal for those who appreciate a lush, vibrant environment, albeit with the possibility of occasional downpours. Visitors are encouraged to enjoy the balmy weather while staying prepared for the rain.
In September, San Diego, Mexico, experiences a transition into the cooler months, with temperatures displaying a balance between warmth and freshness. The minimum temperature dips to a comfortable 9°C (49°F), while the average holds steady at 20°C (68°F), making it an inviting time for outdoor activities. Daytime highs reach up to 31°C (88°F), reflecting lingering summer vibes. Compared to the peak summer months, September displays a noticeable decrease in nighttime temperatures, marking the beginning of a more temperate season. This month serves as a picturesque bridge between the heat of summer and the cooler autumn days ahead, perfect for both locals and visitors to enjoy the beauty of this coastal gem.
In September, San Diego, Mexico, experiences a significant amount of rainfall, accumulating 147 mm (5.8 in) over the course of 17 days. This marks a continuation of the wet season, following closely behind August's substantial precipitation of 145 mm (5.7 in). Interestingly, the summer months—particularly June and July—set the tone with their peak rainfall of 156 mm (6.2 in) and 160 mm (6.3 in) respectively. As September rolls in, the rain sustains its grip, contributing to the lush landscapes typical of this region. This trend not only showcases the potential for heavy seasonal rainfall but also highlights a vital aspect of San Diego's climate, reinforcing the importance of these wet months for both agriculture and local ecosystems. As the year transitions towards October, a notable decrease in precipitation is expected, with just 48 mm (1.9 in) forecasted, hinting at a shift to drier conditions ahead.
In September, San Diego, Mexico, experiences a noticeable uptick in humidity, reaching 81%. This increase signals the transition towards the end of the humid season, following a summer characterized by average levels around 68% in both July and August. The rise in moisture is evident as the region prepares for the more humid months of October and November, where humidity peaks at 83% and 84%, respectively. Notably, September's humidity marks a significant jump compared to the drier months earlier in the year, particularly March and April, when levels hovered around 58%. This seasonal shift highlights San Diego's distinct climate patterns, illustrating how the warm summer months give way to a more humid autumn in this coastal paradise.
In September, San Diego experiences a UV Index of 14, placing it firmly in the extreme exposure category with a burn time of just 10 minutes. This level of solar intensity reflects a consistent trend observed from May through September, whereby the UV Index remains high, indicating a need for ample sun protection. As summer transitions into fall, it's vital for residents and visitors alike to stay vigilant against the sun's rays, as this area showcases some of the highest UV levels of the year. For more detailed information on UV trends throughout the year, visit San Diego UV Index.
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As summer gently transitions to fall, September in San Diego, Mexico, offers a delightful embrace of warmth and sunshine, boasting an impressive 295 hours of sunlight. This month continues the trend of abundant daylight, building on a peak in May with 345 hours. While September shows a slight dip in sunlight compared to the summer months, it still shines brightly compared to the earlier parts of the year, providing a perfect backdrop for outdoor adventures. With the sunshine gradually tapering off into the cooler months, September becomes an ideal time to savor the lingering summer vibes before fall takes hold. The steady availability of sunlight enhances San Diego's attractions, making it a vibrant destination for both locals and travelers alike.
As September rolls in, San Diego, Mexico, tends to experience a noticeable dip in sunny weather, with only a 24% chance of sun. This marks a significant decline compared to the vibrant days of earlier months like February (88%) and March (79%). Following the hot summer, where sunshine is abundant, the transition into fall brings a shift, hinting at the return of milder weather patterns. Notably, September aligns with the lowest likelihood of sunny days, mirroring more overcast conditions commonly observed in the latter summer months. Visitors hoping for bright skies should be aware that this time of year may not deliver the sunny escape they seek.
As September arrives in San Diego, Mexico, the city enjoys a delightful 12 hours of daylight, marking the transition into the autumn season. This month maintains the same daylight duration as August, representing a shift from the peak summer brightness of 13 hours experienced in May through July. Following September, daylight begins to wane as October brings a return to 11 hours. Overall, the progression from winter's shorter days to the summer’s long stretches of sunshine highlights an intriguing seasonal rhythm, where daylight duration slowly fluctuates but remains relatively stable during the summer months, before gently tapering off into the latter part of the year.
As September rolls into San Diego, Mexico, the winds begin to whisper a gentle lull, averaging 1.9 m/s (4 mph), the lowest of the year. This marks a noticeable shift from the breezier months of spring and early summer, where wind speeds hovered around 2.5 m/s (6 mph). Interestingly, while the summer months display a minor dip in wind intensity, it is September that truly ushers in a calmness, perfect for those seeking a tranquil escape. With the cooler months approaching, the wind patterns hint at a gradual recovery, promising a return to slightly stronger breezes in October. Overall, September serves as a transition, embracing the serene while preparing for the subtle vigor that autumn will bring.
The weather in San Diego 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 San Diego and find detailed weather information for every month.
September and January present contrasting weather patterns. In September, temperatures can range significantly from a chilly 9°C (49°F) to a warm 31°C (88°F), with an average of 20°C (68°F). This month receives considerable rainfall, totaling 147 mm (5.8 in) over approximately 17 days, contributing to a high humidity level of 81%. In contrast, January is much cooler, with temperatures ranging from a low of 2°C (36°F) to a high of 29°C (84°F) and an average of 15°C (59°F). The precipitation drops dramatically to just 4 mm (0.2 in) over a mere 1 day, and the humidity decreases to 74%. For a closer look at January weather specifics, you can check out San Diego weather in January.
When comparing the weather in September and February, notable differences emerge. In September, temperatures range from a minimum of 9°C (49°F) to a maximum of 31°C (88°F), with an average temperature of 20°C (68°F). This month also experiences significant rainfall, totaling 147 mm (5.8 in) over 17 days, and a high humidity level of 81%. Conversely, February offers milder temperatures, with a minimum of 4°C (40°F), an average of 17°C (64°F), and a maximum also reaching 31°C (88°F). The stark difference is in precipitation, as February sees just 6 mm (0.2 in) of rain over only 1 day, along with lower humidity at 65%. For a deeper look into the February climate, you can explore San Diego weather in February.
September and March exhibit distinct weather patterns that reflect their transitional roles in the seasons. September typically showcases a wider temperature range, with minimums hovering around 9°C (49°F) and maxima reaching up to 31°C (88°F), along with significant precipitation totaling 147 mm (5.8 in) over about 17 days and high humidity levels at 81%. In contrast, March presents slightly cooler temperatures, with a minimum of 5°C (41°F) and a maximum of 33°C (92°F), but experiences minimal rainfall of just 7 mm (0.3 in) over only 2 days, resulting in much lower humidity at 58%. For more details on weather during this period, you can check San Diego weather in March.
When comparing the weather between September and April, notable differences emerge. September experiences a wider temperature range, with minimums around 9°C and maximums reaching 31°C, leading to an average temperature of 20°C. In contrast, April tends to be warmer on average at 22°C, with maximums soaring to 35°C. While September is characterized by higher humidity at 81% and significant rainfall of 147 mm over 17 days, April boasts much drier conditions, with only 3 mm of precipitation and no rainy days. For more detailed information, you can explore San Diego weather in April.
When comparing the weather in September and May, notable differences emerge. September boasts a minimum temperature of 9°C (49°F) and an average of 20°C (68°F), peaking at 31°C (88°F) with significant rainfall totaling 147 mm (5.8 in) over 17 days and high humidity at 81%. In contrast, May offers warmer temperatures, starting at a minimum of 12°C (53°F) and averaging 23°C (74°F), reaching a maximum of 36°C (97°F). Precipitation in May is much lower at 36 mm (1.4 in) over just 6 days, with humidity at a more comfortable 67%. For more details on the pleasant weather conditions in May, you can check out this link: San Diego weather in May.
In comparing the weather of September and June, distinct differences emerge. September sees a wider temperature range, with minimums dropping to about 9°C (49°F) and maximums reaching up to 31°C (88°F), while June maintains higher temperatures, with minimums around 12°C (54°F) and maximums peaking at 36°C (97°F). Both months experience substantial precipitation, but September tends to be slightly wetter, recording 147 mm (5.8 in) of rainfall over 17 days compared to June's 156 mm (6.2 in) over 15 days. Additionally, September's humidity is higher at 81%, making it feel more humid than the relatively lower 76% in June. For more specific details about June weather, you can check San Diego weather in June.
In comparing the weather in September and July, we see notable differences in temperature and precipitation. September experiences slightly lower minimum temperatures, averaging 9°C (49°F) at night, while July's minimum is a bit warmer at 12°C (54°F). Both months share similar maximum temperatures, peaking around 31°C (88°F) in September and 31°C (89°F) in July, maintaining an average of about 20°C (68°F to 69°F). However, September tends to be wetter, receiving 147 mm (5.8 in) of precipitation over 17 days compared to July's 160 mm (6.3 in) over 20 days. Notably, September is also more humid, with a humidity level of 81%, compared to July's 67%. For those interested in exploring specific weather conditions, this link provides more insight: San Diego weather in July.
In comparing the weather between August and September, both months experienced similar maximum temperatures, reaching up to 31°C (88°F). However, September witnessed lower minimum temperatures, dropping to 9°C (49°F) compared to August's 12°C (54°F). Precipitation levels were slightly higher in September at 147 mm (5.8 in) over 17 days, while August saw 145 mm (5.7 in) over the same number of days. Additionally, September had a noticeably higher humidity level at 81%, in contrast to August's 68%. For more detailed insights, check out San Diego weather in August.
September and October exhibit notable differences in weather patterns. In September, temperatures range from a minimum of 9°C (49°F) to a maximum of 31°C (88°F), with an average of 20°C (68°F). The month is characterized by higher precipitation levels, totaling 147 mm (5.8 in) over 17 rainy days, coupled with a humidity of 81%. In contrast, October sees a slight drop in temperatures, with a minimum of 6°C (43°F) and an average of 19°C (67°F), while still peaking at 31°C (89°F). Precipitation decreases significantly to 48 mm (1.9 in) over just 8 days, and humidity rises slightly to 83%. For a closer look at October weather specifics, visit San Diego weather in October.
In September, the weather is generally warmer with average temperatures reaching around 20°C (68°F), peaking at a maximum of 31°C (88°F). However, it tends to be quite humid at 81%, and there's significant rainfall totaling 147 mm (5.8 in) over 17 days. In contrast, November brings cooler temperatures with an average of 17°C (63°F), a minimum of 2°C (36°F), and a maximum of 30°C (87°F). Notably, November sees a significant reduction in precipitation, with only 16 mm (0.6 in) falling over just 2 days and slightly higher humidity at 84%. For more detailed information, you can visit San Diego weather in November.
September and December present contrasting weather patterns. In September, temperatures range from a minimum of 9°C (49°F) to a maximum of 31°C (88°F), with an average of 20°C (68°F). This month also experiences significant rainfall, with approximately 147 mm (5.8 in) of precipitation over 17 days, contributing to a high humidity level of 81%. In contrast, December sees cooler temperatures, with a minimum of 1°C (34°F) and a maximum of 29°C (84°F), averaging 15°C (59°F). Notably, December is much drier, with only 4 mm (0.1 in) of rain falling over just 1 day, while humidity remains steady at 81%. For more specific insights, check out San Diego weather in December.
As September unfolds in San Diego, it marks a transition from the warmer summer months, bringing a delightful average temperature that's still pleasantly warm yet significantly cooler than the peak heat of July and August. With the humidity at a comfortable 81%, this month often feels just right for enjoying the city's beautiful coastal scenery. However, September also brings increased precipitation, as evidenced by an uptick in rainy days compared to the drier months preceding it. This blend of warmth and occasional showers distinguishes September from the sun-soaked summers, making it a unique time to experience San Diego’s vibrant climate. For further insights into the varied weather patterns of the area, visit San Diego Climate.