Last updated: February 24, 2025
August in National Harbor, United States is characterized by warm temperatures and significant humidity. With a maximum temperature reaching 37°C (99°F) and an average of 25°C (78°F), visitors can expect sunny days, though they should prepare for cooler evenings with the temperature dipping to a minimum of 15°C (59°F). The month sees an average of 15 rainy days, accumulating a precipitation total of 146 mm (5.7 in), contributing to a humidity level of 72%. This blend of warmth and moisture creates a vibrant, albeit occasionally wet, summer atmosphere perfect for both outdoor activities and relaxation.
In August, National Harbor experiences its warmest days of the year, with temperatures ranging from a comfortable 15°C (59°F) at night to a sizzling 37°C (99°F) during peak hours. The average temperature settles at a pleasant 25°C (78°F), making it an ideal time for outdoor activities and waterfront enjoyment. As summer progresses, the city transitions from the moderate temperatures of July to the heat of August, showcasing a trend of increasing warmth. With humidity levels rising, the vibrant atmosphere of National Harbor draws both locals and visitors alike, eager to soak up the sun and engage in the lively cultural scene.
August in National Harbor is characterized by its peak precipitation, with an impressive 146 mm (5.7 in) of rainfall. This marks the month as not only the wettest of the year but also a continuation of a progressive increase in rainfall since the drier winter months. With rainfall occurring on 15 days, August sees a notable uptick in precipitation days compared to the preceding months, reflecting the transition into late summer storms. This trend of increasing rainfall reaches its zenith just before a gradual decline begins in September, setting the stage for the drier fall season ahead. Overall, August stands out as a time when the lush surroundings of National Harbor are nourished, creating a vibrant landscape that highlights the dynamic climate of the region.
In August, National Harbor experiences a notable decline in humidity, averaging 72%, marking it as one of the driest months of the year. This reduction follows a gradual downward trend from January's high of 84%, with humidity consistently decreasing through the summer. By July, levels drop to 74%, indicating a shift towards more comfortable conditions as the season transitions. Interestingly, the humidity rises again in September, creeping back up to 75%, hinting at the lingering warmth of summer. Overall, August stands out as a transitional month, providing a brief respite from the heavier humidity experienced earlier in the year.
In August, the UV Index in National Harbor remains notably high, sitting at 9 and categorized as very high, which signals that sunburn can occur quickly with unprotected exposure. This month typically sees a slight dip from the peak UV Index of 10 experienced in June and July, but individuals should still be cautious, as the burn time is just 15 minutes. As summer progresses, maintaining sun safety becomes increasingly critical, emphasizing the importance of protective measures during outdoor activities. To stay informed about UV levels and plan accordingly, check out the National Harbor UV Index.
UV Risk Categories
As summer wanes in National Harbor, August brings a significant 321 hours of sunshine, a dazzling continuation of the brilliant rays experienced in the previous months. After a peak in July with 357 hours, sunlight begins to taper, yet August still showcases ample opportunities for outdoor enjoyment. This month sits comfortably nestled among the year’s sunniest periods, reflecting a broader trend of increasing daylight from January's modest 153 hours to summer's radiant highs. With transitions evident from the vibrant brightness of mid-summer to the softer glow of early autumn, August stands as a perfect time to savor the lingering warmth before the days gradually shorten.
In National Harbor, August typically sees a 35% chance of sunny weather, making it one of the cooler months for sunshine compared to its summer counterparts. This figure is somewhat lower than the peaks of July at 49% and the promise of September, which boasts a sunnier 55%. As we look back through the year, it appears that the chances of basking in the sun tend to fluctuate, with notable highs in the late summer and fall months, especially November, which surprises with a 58% likelihood. Overall, while August may not offer the sunniest days, it still holds its own charm amid more temperate conditions.
As summer wanes in August, National Harbor experiences a subtle shift in daylight, offering about 13 hours of sunlight. This decline from the peak of 14 hours in June and July signals the transition towards the shorter days of fall. The gradual decrease in daylight hours reflects the natural ebb of summer, with each month inching closer to winter’s minimalist glow of just 9 hours in December. Notably, the daylight duration during August remains robust compared to the early months of the year, such as January, with its mere 9 hours. As we prepare for the upcoming seasons, August stands as a vibrant reminder of summer's lingering warmth before giving way to autumn's embrace.
In August, the wind in National Harbor exhibits a notable decrease, with an average speed dropping to just 1.9 m/s (4 mph), marking the calmest month of the year. This gentle breeze contrasts sharply with the more robust winds of earlier months, where speeds hovered around 3.2 m/s (7 mph) from January to April. As summer progresses, the winds gradually weaken, reaching their minimum in August before picking up again in September at 2.5 m/s (6 mph). This trend underscores a seasonal rhythm, where the summer heat brings a softer touch on the breeze, inviting residents and visitors alike to savor the tranquil atmosphere of the waterfront.
The weather in National Harbor changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of August's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in National Harbor and find detailed weather information for every month.
August and January showcase strikingly contrasting weather patterns. In August, temperatures range from a mild 15°C (59°F) to a scorching 37°C (99°F), with an average of 25°C (78°F) and a significant 146 mm (5.7 in) of rainfall spread over 15 days, creating a humid environment with 72% humidity. In stark contrast, January experiences much colder conditions, with minimum temperatures plummeting to -14°C (7°F) and a maximum of 22°C (71°F), averaging just 3°C (38°F). Precipitation in January is lighter, totaling 61 mm (2.4 in) over 7 days, and the humidity is higher at 84%. For more details on winter weather, check out National Harbor weather in January.
The contrast between August and February weather is striking. In August, temperatures range from a minimum of 15°C (59°F) to a scorching maximum of 37°C (99°F), with an average of 25°C (78°F) and a humid environment at 72%. In stark contrast, February experiences much colder conditions, with temperatures plummeting to a minimum of -14°C (7°F) and reaching a maximum of 27°C (81°F), while the average hovers around 5°C (42°F). Additionally, February, despite having less overall precipitation than August, features higher humidity at 83%. For more insights into February weather, you can check National Harbor weather in February.
August and March present stark contrasts in weather. August boasts a warm average temperature of 25°C (78°F), with maximums reaching up to 37°C (99°F), creating a hot and humid atmosphere, with 72% humidity. The month is also characterized by significant rainfall, totaling 146 mm over 15 days. In contrast, March offers a much cooler climate, with average temperatures around 8°C (47°F) and a maximum of 29°C (84°F). While March can still bring variability, it generally receives less precipitation at 82 mm over 9 days and has a higher humidity of 83%. For more details on March weather, you can check National Harbor weather in March.
In comparing the weather of August and April, it's clear that August is considerably warmer, with average temperatures reaching 25°C (78°F) compared to April's average of only 14°C (58°F). August experiences higher maximum temperatures as well, soaring up to 37°C (99°F), while April can peak at 33°C (92°F). However, April has a notable chill, with minimum temperatures dropping to -1°C (31°F), contrasting starkly with August's milder low of 15°C (59°F). Furthermore, while both months see rainfall, August has more precipitation at 146 mm (5.7 in) over around 15 days, compared to April’s 102 mm (4.0 in) across 11 days. Additionally, April tends to be more humid, with levels around 81%, versus August's 72%. For more details, you can check National Harbor weather in April.
When comparing the weather in August to that of May, notable differences emerge. August generally features higher temperatures, with a minimum of 15°C and an average of 25°C, peaking at a sweltering 37°C. In contrast, May starts cooler with minimums around 3°C and an average of 19°C, while reaching a maximum of 35°C. Precipitation levels are relatively close, with August receiving 146 mm over 15 days and May collecting 121 mm over 12 days, although August also has slightly lower humidity at 72% compared to May's 78%. For a closer look at the conditions during May, check out National Harbor weather in May.
In comparing the weather of August and June, we observe notable differences in temperature and precipitation patterns. August tends to be warmer, with an average temperature of 25°C (78°F) compared to June's average of 24°C (76°F). Both months experience a maximum temperature of 37°C (99°F) and 37°C (98°F) respectively. However, August sees higher precipitation levels, totaling 146 mm (5.7 in) over 15 days, while June has 107 mm (4.2 in) over 13 days. Humidity is slightly lower in August at 72%, compared to June's 79%. For more specifics on June weather, you can visit National Harbor weather in June.
In comparing the weather between August and July, we see some notable differences. August features slightly cooler temperatures, with an average of 25°C (78°F) compared to July's warmer 27°C (81°F). While July reaches a higher maximum temperature of 38°C (102°F), August's peak is 37°C (99°F). Precipitation levels in August are slightly higher at 146 mm (5.7 in) over 15 days, while July experiences 132 mm (5.2 in) over 12 days. Humidity remains fairly consistent, with July at 74% and August at 72%. For more specific weather insights, you can visit National Harbor weather in July.
August weather is characterized by warmer temperatures, ranging from a minimum of 15°C (59°F) to a maximum of 37°C (99°F), with an average of 25°C (78°F). The month sees significant precipitation, totaling 146 mm (5.7 in) over 15 days, and maintains a humidity level of 72%. In contrast, September experiences cooler temperatures, with a minimum of 6°C (44°F), an average of 22°C (73°F), and the same maximum of 37°C (99°F). Precipitation decreases to 93 mm (3.7 in) over 11 days, and humidity rises slightly to 75%. For a detailed look at September's weather, check out National Harbor weather in September.
August and October present a stark contrast in weather patterns. In August, temperatures soar with a minimum of 15°C (59°F) and an average high of 25°C (78°F), peaking at a sweltering 37°C (99°F). The month is also characterized by significant rainfall, totaling 146 mm (5.7 in) across 15 days, along with a humidity level of 72%. In comparison, October features more mild temperatures, with a minimum of 2°C (36°F) and an average of 17°C (63°F), while still reaching up to 36°C (97°F) on warmer days. Precipitation decreases to 105 mm (4.2 in) spread over just 9 days, and humidity rises slightly to 81%. For more detailed weather information, you can check National Harbor weather in October.
In August, temperatures are warm to hot, with a minimum of 15°C (59°F) and averaging around 25°C (78°F), while max temperatures can reach a sweltering 37°C (99°F). This month experiences significant rainfall, averaging 146 mm (5.7 in) over 15 days, combined with a humidity level of 72%. In contrast, November brings much cooler weather, with temperatures ranging from a minimum of -5°C (23°F) to an average of 9°C (48°F), peaking at a comfortable 26°C (78°F). Precipitation decreases to 77 mm (3.0 in), occurring on just 7 days, although humidity rises slightly to 85%. For more detailed insights on November weather, check out National Harbor weather in November.
August weather is characterized by warmth and significant humidity, with temperatures ranging from a minimum of 15°C (59°F) to a maximum of 37°C (99°F) and an average of 25°C (78°F). This month also sees considerable rainfall, averaging 146 mm (5.7 in) over about 15 days, making it a relatively wet period. In contrast, December brings much colder temperatures, with a minimum of -10°C (14°F) and an average of 5°C (42°F), peaking at a maximum of 20°C (69°F). The month tends to be drier, with 89 mm (3.5 in) of precipitation spread over 9 days, though the humidity is slightly higher at 84%. For more detailed information on what to expect during December, you can visit National Harbor weather in December.
As summer reaches its peak in August, National Harbor experiences notably high temperatures, contrasting with the milder months preceding it. While days can turn scorching, averaging around 25°C (78°F), the frequent humid conditions can make it feel even warmer. Visitors can expect a fair amount of rainfall, with about 15 days of precipitation, adding to the vibrant summer atmosphere. This month stands out for its humidity levels and the potential for sudden summer showers, creating a dynamic weather experience. For a deeper dive into weather patterns and the National Harbor Climate, National Harbor Climate is an excellent resource.