Last updated: February 24, 2025
September in San Luis Obispo offers a delightful blend of warm temperatures and low humidity, making it an ideal time to enjoy outdoor activities. With maximum highs reaching 35°C (95°F) and an average temperature of 18°C (65°F), residents and visitors can bask in the warmth, especially during the day. Nights cool down to a refreshing 11°C (53°F), providing a comfortable respite. Remarkably, this month sees minimal precipitation, with only 1 mm recorded, ensuring clear skies for most of the month. Coupled with a humidity level of 70%, September presents a perfect opportunity to explore the beauty of San Luis Obispo without the worry of rain.
In September, San Luis Obispo experiences a delightful transition as summer begins to wane. The temperatures range from a minimum of 11°C (53°F) to a peak of 35°C (95°F), showcasing a notable warmth that lingers from the summer months. With an average temperature settling around 18°C (65°F), residents and visitors alike enjoy pleasant evenings under the stars. This month stands out with its highest maximum temperature of the year, making it an ideal time for outdoor activities before the cooler autumn days arrive. The slight dip in evening temperatures hints at the seasonal shift, yet September’s warmth still invites adventures, whether it’s a beach day or a cozy gathering around a fire pit.
In September, San Luis Obispo experiences a notable trend of minimal precipitation, with only 1 mm (0.0 inches) recorded throughout the month, marking it as a continuation of the dry spell seen during the summer. This starkly contrasts with the earlier months, where January and March exhibited significant rainfall, totaling 110 mm (4.3 inches) and 84 mm (3.3 inches) respectively. Interestingly, September sees no precipitation days, reflecting the region's transition into the dry season. As the year progresses, October brings a slight uptick in rainfall with 10 mm (0.4 inches), but it's evident that September remains a dry and tranquil month in the climatological calendar of San Luis Obispo.
As summer fades into autumn, September in San Luis Obispo brings a noticeable dip in humidity, falling to a comfortable 70%. This trend marks a decline from the more humid months of summer, where humidity levels hovered around 72% in August and reached 75% in July. This gradual decrease reflects a broader seasonal shift, as humidity peaks in the winter months with levels reaching 80% or more. The transition from high humidity in the earlier part of the year to a more moderate level by September creates an inviting atmosphere, perfect for enjoying the region's natural beauty and outdoor activities. As the year progresses, residents and visitors alike can revel in the crisp, refreshing air that accompanies the fall, making San Luis Obispo a delightful destination.
As September rolls into San Luis Obispo, the UV Index remains elevated at 9, placing it in the very high exposure category, with a burn time of just 15 minutes for unprotected skin. This marks a slight dip from the scorching summer months, where July and August pushed the index to 12 in the extreme range, demanding heightened sun safety precautions. However, it is a reminder that as we transition into fall, sun protection is still essential, particularly during midday hours. Observing this trend, it's clear that while the risk may ease with the change of seasons, vigilance is key to enjoying the beautiful outdoor weather in San Luis Obispo. For more details on sun safety, visit San Luis Obispo UV Index.
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September in San Luis Obispo continues the sunny trend that sweeps through the summer months, offering a delightful 316 hours of sunshine. While this marks a slight dip from the sun-drenched 383 hours of July, it's still vibrant compared to the preceding months. The consistent warmth lingers from summer, making September a splendid time to enjoy the outdoors. As the year progresses into autumn, there's a noticeable decrease in daylight hours, with October bringing 295 hours, yet September stands out as a bridge between the summer glow and the cooler fall days, perfect for savoring the captivating landscapes of this charming Californian locale.
In San Luis Obispo, September maintains a pleasant likelihood of sunny weather, with a 68% chance of sun. This month's conditions continue the trend of bright and sunny days that began in late spring, peaking in June, when the sun graces the city 73% of the time. August follows closely with 71% sun, and while September sees a slight dip, it remains among the sunniest months of the year. As the region transitions into fall, the consistent chances of sunshine create perfect opportunities for outdoor activities, reflecting the overall favorable climate that characterizes this beautiful coastal area.
As September unfolds in San Luis Obispo, residents and visitors alike enjoy a gentle decline in daylight, with the month averaging 12 hours of sunlight. This marks a subtle shift from the summer months of June to August, where 14 hours of daylight created long, vibrant days perfect for outdoor adventures. While daylight begins to wane leading into October, the warm hues of early autumn linger, providing a picturesque backdrop for leisurely strolls and sunset views. This gradual transition in daylight hours not only signifies the arrival of fall but also invites a cozy ambiance, reminding everyone of the beautiful cyclical rhythms of nature.
As summer transitions into fall, September in San Luis Obispo greets residents and visitors with its characteristic mildness, reflecting a continuation of the calm winds experienced in the preceding months. With an average wind speed of 2.1 m/s (5 mph), this month ties with August for the lightest breezes of the year. The steady decline in wind speeds since the start of summer, peaking at 3.5 m/s in January, illustrates a gentle shift towards the more tranquil autumn ambiance. As the season unfolds, these soothing winds create a perfect backdrop for leisurely outdoor activities, making September an ideal time to experience the natural beauty of this charming coastal city.
The weather in San Luis Obispo 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 Luis Obispo and find detailed weather information for every month.
September and January present contrasting weather patterns. In September, temperatures can soar with a minimum of 11°C (53°F) and a maximum reaching 35°C (95°F), resulting in an average of 18°C (65°F) and virtually no precipitation. The humidity sits at a moderate 70%, making it a warm and dry month. In contrast, January brings cooler conditions with temperatures ranging from a minimum of 4°C (40°F) to a maximum of 23°C (74°F), leading to an average of 12°C (54°F). This winter month experiences significant rainfall, with 110 mm (4.3 in) spread over about six days, along with a higher humidity of 80%. To learn more about the weather specifics in January, visit San Luis Obispo weather in January.
September typically enjoys warm weather with an average temperature of 18°C (65°F) and highs reaching up to 35°C (95°F), making it one of the hottest months of the year. The month experiences very little rainfall, with only 1 mm recorded and no rainy days, accompanied by a moderate humidity level of 70%. In contrast, February presents a much cooler climate, featuring average temperatures of 12°C (54°F) and maximums of 25°C (77°F). It is significantly wetter, with 80 mm of precipitation over six days and a higher humidity level at 83%. For more detailed information, check out San Luis Obispo weather in February.
In September, the weather typically features warmer temperatures, with a minimum of 11°C (53°F), an average of 18°C (65°F), and a maximum reaching up to 35°C (95°F). This month is characterized by very little precipitation, with only 1 mm recorded and no rainy days, along with a humidity level of 70%. In stark contrast, March brings cooler temperatures, with a minimum of 5°C (41°F), an average of 13°C (55°F), and a maximum of 24°C (76°F). March is also much wetter, experiencing 84 mm of precipitation over 9 days and higher humidity at 80%. For a detailed look at the weather specifics of March, check out San Luis Obispo weather in March.
When comparing the weather in September and April, we see notable differences in temperature and precipitation. September typically boasts warmer temperatures, with a minimum of 11°C (53°F) and maximum reaching up to 35°C (95°F), while April is cooler, starting at a minimum of 7°C (44°F) and peaking at 26°C (80°F). In terms of precipitation, September is remarkably dry, with no recorded rainfall, whereas April experiences an average rainfall of 23 mm (0.9 in) over three days, contributing to a higher humidity level of 76% compared to September's 70%. For more detailed insights on weather patterns, you can visit San Luis Obispo weather in April.
In comparing the weather between September and May, September generally boasts warmer temperatures, with an average of 18°C (65°F) rising to a maximum of 35°C (95°F). In contrast, May is cooler, with an average temperature of 15°C (59°F) and a maximum of only 25°C (77°F). While September experiences negligible precipitation and humidity at 70%, May sees slightly more rainfall (12 mm) over two days and a higher humidity level of 75%. For more detailed information on May weather, check San Luis Obispo weather in May.
September and June both showcase mild temperatures, but September tends to be warmer overall. In September, the minimum temperature is around 11°C (53°F), with an average of 18°C (65°F) and a maximum reaching 35°C (95°F). In contrast, June starts with a slightly cooler average temperature of 16°C (62°F) and a maximum of 31°C (88°F). Both months experience minimal precipitation, with just 1 mm reported and no precipitation days recorded. Humidity levels are comparable, with September at 70% and June slightly higher at 74%. For more insights on June weather, check out San Luis Obispo weather in June.
In comparing the weather of September and July, we see that both months have similar average temperatures around 18°C (65°F). However, September can experience a slightly broader temperature range, with minimums of 11°C (53°F) and maximums reaching 35°C (95°F), compared to July’s minimum of 12°C (55°F) and maximum of 31°C (89°F). Both months share an extremely low level of precipitation, at just 1 mm and no rainy days, but September has a slightly lower humidity level at 70% compared to July's 75%. For more details, you can check San Luis Obispo weather in July.
In comparing the weather of September and August, it's notable that September tends to be slightly warmer, with a maximum temperature reaching up to 35°C (95°F) compared to August's 31°C (88°F). The average temperatures are similar, at 18°C (65°F) for both months, but September experiences a lower minimum temperature of 11°C (53°F) compared to August's 13°C (55°F). Precipitation remains minimal for both months, with 1 mm recorded and no rainy days in either month. Humidity is slightly lower in September at 70%, versus 72% in August. For more insights on the weather during this time, you can check San Luis Obispo weather in August.
In September, the weather boasts a warm range with minimum temperatures around 11°C (53°F) and maximums peaking at 35°C (95°F), accompanied by very little precipitation and high humidity levels of 70%. Transitioning into October, the temperatures dip slightly, with lows reaching 9°C (49°F) and highs around 33°C (92°F), while the average temperature decreases to 17°C (64°F). Rainfall becomes more noticeable in October, with a total of 10 mm (0.4 in) recorded, yet the humidity remains consistent at 70%. For more detailed insights, check out the San Luis Obispo weather in October.
September and November present quite distinct weather profiles. In September, temperatures can soar with a minimum of 11°C (53°F) and a maximum reaching up to 35°C (95°F), averaging around 18°C (65°F). The month is characterized by dry conditions, with negligible precipitation of just 1 mm and no rainy days, alongside a humidity level of 70%. In contrast, November's temperatures drop, featuring a minimum of 6°C (42°F) and a maximum of 26°C (79°F), with an average of 15°C (59°F). This month brings a notable increase in precipitation, totaling 32 mm over three days, and humidity rises slightly to 74%. For more detailed insights into November’s weather, you can check San Luis Obispo weather in November.
In September, the weather is generally warm, with temperatures ranging from a cool 11°C (53°F) at night to a high of 35°C (95°F) during the day, and it remains dry with only 1 mm of precipitation over the month. In contrast, December sees a significant drop in temperature, with minimums of 5°C (42°F) and daytime highs of 23°C (74°F), along with increased rainfall totaling 76 mm (3.0 in) spread over about six days. The humidity also rises slightly from September to December, moving from 70% to 76%. For more detailed insights, you can check San Luis Obispo weather in December.
As September rolls into San Luis Obispo, the weather showcases a delightful transition, setting the stage for warm days and cool evenings. With maximum temperatures reaching a pleasant 35°C, the average feels comfortable, hovering around 18°C, while nights cool down pleasantly to around 11°C. This month stands out with its strikingly low precipitation, showcasing a dry spell with no rainy days, unlike the wetter months that precede it. The humidity stays moderate at 70%, making the warmth feel inviting rather than stifling. Overall, September invites outdoor activities and a true sense of Californian living, offering an optimal blend of sun and mild temperatures. For a deeper insight into what to expect throughout the year, check out San Luis Obispo Climate.