Last updated: February 24, 2025
In September, Rainier, United States experiences a delightful blend of warm days and cool nights. With maximum temperatures reaching 30°C (87°F), the average sits comfortably at 16°C (62°F), while the minimum dips to a refreshingly cool 6°C (43°F). This month welcomes 85 mm (3.4 in) of rainfall spread over approximately 10 days, creating a lush landscape that thrives under a humidity level of 74%. Whether you're exploring the vibrant outdoors or enjoying cozy indoor activities, September in Rainier offers a charming variety of weather experiences.
In September, temperatures in Rainier, United States, begin to shift towards the cooler fall months, featuring a minimum of 6°C (43°F) and an average of 16°C (62°F). The maximum temperature can still reach a warm 30°C (87°F), indicating a lingering warmth as summer fades. This pattern highlights a gradual decline in both early mornings and nights, offering a comfortable transition period. The month serves as a crisp reminder of the changing seasons, blending the warmth of summer with the fresh breezes of autumn, making it a delightful time to explore the outdoors while enjoying the vibrant colors that begin to emerge.
In September, Rainier experiences a noticeable uptick in precipitation, with 85 mm (3.4 in) of rainfall over 10 days. This marks a significant increase from the July and August dry spells, where the total precipitation was just 10 mm (0.4 in) and 13 mm (0.5 in), respectively. As summer transitions to fall, the atmosphere begins to shift, leading to a more consistent pattern of rainfall that foreshadows the wetter months ahead. Notably, September’s precipitation serves as a bridge, preparing the landscape for the more intense downpours of October and November, which typically see higher rainfall amounts of 134 mm (5.3 in) and 182 mm (7.2 in). This seasonal rhythm highlights how variable weather patterns can paint a vibrant picture of the changing seasons in Rainier.
In September, Rainier experiences a slight drop in humidity, with levels hovering around 74%. This marks a continuation of the lower humidity trend that begins in late summer, where August sees a more pronounced decrease to 73%. The transition into fall brings a relief from the higher moisture commonly felt during the winter months, which average above 86%. As the year progresses, humidity levels gradually rise again, peaking in the colder months. Overall, September serves as a transitional period, bridging the drier summer air to the more humid conditions that fill the later part of the year.
As September rolls into Rainier, the UV Index presents a high exposure level of 7, signaling it's time to take sun safety more seriously with a burn time of just 25 minutes. This month marks a slight decrease from the peak summer months of July and August, which both recorded a very high index of 9. However, September's values still indicate a substantial risk, especially for those spending prolonged time outdoors. Interestingly, this month serves as a transitional period, foreshadowing a return to moderate levels in October. With fall approaching, it's essential to stay aware of UV intensity, even as temperatures cool. For detailed insights on UV trends throughout the year, visit Rainier UV Index.
UV Risk Categories
In Rainier, United States, September is a delightful transition from the sun-drenched summer months into the cooler fall season, boasting 254 hours of sunshine. This month showcases a noticeable dip from the peak brightness of July, which basks in an impressive 364 hours of sunlight. Yet, September still shines brighter than the earlier months of the year, such as January and February, which struggle with just 81 and 122 hours respectively. The gradual decline from summer peaks indicates a shift towards autumn, while also allowing for bright days that encourage outdoor activities. As the days grow shorter, residents and visitors alike relish these warm, sunny afternoons, creating a beautiful backdrop for the changing leaves.
In Rainier, United States, September experiences a modest likelihood of sunny weather, with a 36% chance of sunshine. This figure reflects a noticeable dip from the sunnier heights of summer, where July peaks at 62% and August settles at 50%. As autumn approaches, the transition is clear; the chances of clear skies drop significantly from the vibrant summer months. However, compared to the upcoming fall months—October and November, with only 23% and 14% chances of sun, respectively—September still retains a degree of brightness, offering a pleasant backdrop for outdoor activities before the gray clouds of winter roll in.
As September rolls in, Rainier, United States, begins to experience a noticeable shift in daylight duration, offering around 12 hours of sunlight. This marks a decline from the peak of 15 hours in the summer months, reflecting the natural progression towards autumn. The trend from spring through summer showcases steadily increasing daylight, culminating in the longest days of the year during June and July. However, September initiates a gradual downward trend as the days grow shorter, leading into October and November with just 10 and 9 hours of daylight, respectively. This beautiful transition not only ushers in a new season but also invites residents and visitors to enjoy the rich hues of early fall beneath the softening sun.
As September unfolds in Rainier, United States, the wind greets the season with a gentle whisper, averaging 2.5 m/s (6 mph). This steady breeze marks a subtle transition from the slightly higher wind speeds of earlier months, with the summer months of July and August recording some of the calmest conditions. As autumn approaches, it’s notable that September maintains a consistency reminiscent of spring, echoing the 2.5 m/s average seen in April and May. Looking ahead, October hints at a slight uptick in winds, suggesting a shift that might invigorate the landscape as it prepares for the cooler months. Overall, September's winds offer a tranquil yet transitional backdrop, setting the stage for the dynamic changes that lie ahead.
The weather in Rainier 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 Rainier and find detailed weather information for every month.
In September, temperatures range from a mild 6°C (43°F) at night to a warm 30°C (87°F) during the day, with an average of 16°C (62°F). The month typically experiences about 85 mm (3.4 in) of precipitation over roughly 10 days, coupled with a humidity level of 74%. In contrast, January brings much cooler conditions, with temperatures dipping as low as -6°C (22°F) and averaging only 5°C (42°F). The maximum temperature rarely exceeds 14°C (57°F), and precipitation increases significantly to 185 mm (7.3 in) spread over 17 days, accompanied by a higher humidity level of 86%. For more details on the weather during January, you can check Rainier weather in January.
When comparing the weather in September and February, it's evident that September enjoys a wider temperature range, with averages around 16°C (62°F) and maximum temperatures reaching up to 30°C (87°F). In contrast, February experiences much cooler conditions, with average temperatures around 5°C (41°F) and lows dropping to -5°C (24°F). Additionally, February is noticeably wetter, receiving 163 mm (6.4 in) of precipitation over 17 days, compared to September's 85 mm (3.4 in) over just 10 days. The humidity levels are also higher in February at 84%, compared to September's 74%. For more details on February weather, you can visit Rainier weather in February.
When comparing the weather in September and March, it's clear that September tends to be warmer, with average temperatures reaching 16°C (62°F) and maximums soaring up to 30°C (87°F). In contrast, March has a cooler average of just 7°C (45°F) and can dip to a minimum of -1°C (31°F). Precipitation is more frequent in March, with 131 mm (5.2 in) over 17 days compared to September's 85 mm (3.4 in) over 10 days. Humidity levels are also higher in March at 85%, compared to September's 74%. For a more detailed look at rain patterns, check out Rainier weather in March.
September and April present contrasting weather patterns. September boasts a warmer average temperature of 16°C (62°F), peaking at a maximum of 30°C (87°F), while April's temperatures range from a chilly -1°C (31°F) to a milder 24°C (75°F), with an average of 10°C (50°F). Although September has slightly lower precipitation at 85 mm (3.4 in) over about 10 days, April sees increased rainfall, totaling 116 mm (4.6 in) across 15 days. Additionally, humidity levels are higher in April at 83%, compared to September's 74%. These differences highlight the transition from summer's warmth to the cooler, wetter spring conditions. For more details, check out Rainier weather in April.
When comparing the weather in September and May, September generally presents slightly warmer conditions. The average temperature in September reaches 16°C (62°F) compared to May's average of 13°C (56°F). Both months can experience maximum temperatures hitting 30°C (86°F), though September also sees a higher maximum at 30°C (87°F). In terms of precipitation, September has more rainfall with 85 mm (3.4 in) over approximately 10 days, while May accumulates 62 mm (2.5 in) with rainfall on about 11 days. Additionally, humidity levels are relatively high in both months, with September at 74% and May slightly higher at 84%. For more detailed insights on weather during this month, check out Rainier weather in May.
When comparing the weather in September and June, it becomes clear that both months exhibit mild averages but vary significantly in their extremes. September starts off with temperatures ranging from a minimum of 6°C (43°F) to a maximum of 30°C (87°F), while June boasts slightly cooler minimums of 7°C (45°F) but can reach a scorching maximum of 38°C (101°F). In terms of precipitation, September is wetter, averaging 85 mm (3.4 in) over about 10 days, compared to June's milder 52 mm (2.1 in) over 8 days. Additionally, humidity levels are higher in June at 84%, compared to September's 74%. These climate conditions highlight the transition from the heat of early summer into the milder, wetter early autumn. For more details, visit Rainier weather in June.
When comparing the weather in September and July, we observe some notable differences. September typically showcases a wider temperature range, with minimums reaching as low as 6°C (43°F) and maximums peaking at 30°C (87°F), presenting an average temperature of 16°C (62°F). In contrast, July's temperatures are generally warmer, with minimums around 10°C (50°F) and maximums hitting 33°C (91°F), leading to an average of 19°C (66°F). Additionally, September experiences more precipitation, with 85 mm (3.4 in) over 10 days, while July is relatively dry, receiving only 10 mm (0.4 in) over 2 days. Notably, humidity in September is slightly lower at 74% compared to July’s 82%. For a closer look at the specifics of July weather, you can refer to Rainier weather in July.
In comparing the weather between August and September, we see notable differences in temperature and precipitation. September experiences a wider temperature range, with minimums dipping to 6°C (43°F) compared to August's milder minimum of 10°C (50°F). While the average temperature in September is slightly cooler at 16°C (62°F) versus August's 19°C (66°F), September can still reach a maximum of 30°C (87°F), although this is lower than August's peak of 34°C (94°F). Precipitation also increases significantly in September, with 85 mm (3.4 in) falling over 10 days, in contrast to August's relatively dry conditions, which only saw 13 mm (0.5 in) over 3 days. Humidity levels remain similar between the two months, with September slightly higher at 74% compared to August's 73%. For more details on the weather patterns in August, you can check Rainier weather in August.
September and October exhibit noticeable shifts in weather patterns. In September, temperatures range from a mild minimum of 6°C (43°F) to a warm maximum of 30°C (87°F), with an average of 16°C (62°F). Precipitation during this month totals 85 mm (3.4 in) over 10 rainy days, accompanied by a humidity level of 74%. In contrast, October sees a drop in average temperatures, with minimums reaching 1°C (34°F) and maximums only reaching 24°C (75°F), resulting in an average of 11°C (52°F). This month also experiences increased precipitation, totaling 134 mm (5.3 in) over 13 days, and higher humidity at 83%. This transition highlights a shift towards cooler, wetter conditions. For more specific details about October weather, you can visit Rainier weather in October.
September typically experiences warmer temperatures, with averages around 16°C (62°F) and maximums reaching up to 30°C (87°F). In contrast, November brings a significant drop in temperature, averaging just 8°C (46°F) and peaking at 17°C (62°F). While September enjoys relatively moderate rainfall of 85 mm (3.4 in) over about 10 days, November sees a notable increase in precipitation, totaling 182 mm (7.2 in) across 17 days, indicating a wetter month. The humidity also rises in November, reaching 86% compared to September's 74%. For more details on November conditions, you can check Rainier weather in November.
September and December weather present stark contrasts. In September, temperatures range from a minimum of 6°C (43°F) to a warm average of 16°C (62°F), reaching a maximum of 30°C (87°F). The month experiences moderate rainfall, with about 85 mm (3.4 in) of precipitation over 10 days and an average humidity of 74%. In contrast, December sees much colder conditions, with temperatures dropping to a minimum of -6°C (22°F) and an average of just 5°C (42°F), peaking at 13°C (56°F). This winter month is significantly wetter, with precipitation totaling 199 mm (7.8 in) across 18 days and higher humidity at 87%. For more detailed insights, check out Rainier weather in December.
As September rolls in, Rainier experiences a significant shift in weather, with warmer daytime temperatures that invite outdoor exploration while contrasting with cooler nights that hint at the approaching autumn. The average heat, coupled with a moderate level of humidity at 74%, creates a comfortable atmosphere for visitors and locals alike. However, the month also brings a noticeable uptick in precipitation days, with 10 rainy days contributing to a total of 85 mm of rainfall—marking a transition from the drier summer months to the wetter fall season. This blend of warmth and moisture adds a unique charm to Rainier in September, inviting everyone to embrace the changing landscape. For more insights on seasonal changes, check out Rainier Climate.