Seattle, Washington, boasts a unique climate that varies noticeably throughout the year, making it a fascinating city for weather enthusiasts.
The warmest time of year is from June to mid-September, with daily high temperatures often exceeding 72°F.
August stands out as the hottest month, hitting an average high of 77°F and a low of 58°F.
During the cooler months, stretching from mid-November to the end of February, temperatures drop significantly.
The average daily high temperature falls below 53°F, providing a stark contrast to the warm season.
Seattle experiences measurable precipitation on about 150 days each year, which means rain lovers are likely to enjoy the weather in this city.
Seattle’s climate is categorically Mediterranean with warm summers, as indicated by the Köppen climate classification Csb.
This temperate nature means that despite its rainy reputation, Seattle enjoys a mix of mild and enjoyable weather conditions throughout the year.
For more specific details on Seattle’s average weather by month, visit the Climate and Average Weather Year Round in Seattle page.
Average Temperature in Seattle, Washington
Seattle experiences mild temperatures year-round.
The warmest month is August, with an average high temperature of 77°F and a low around 58°F.
In contrast, January is the coolest month, with average highs around 47°F and lows near 38°F.
Monthly Breakdown
- January: High 47°F, Low 38°F
- February: High 50°F, Low 39°F
- March: High 55°F, Low 42°F
- April: High 60°F, Low 45°F
- May: High 67°F, Low 50°F
- June: High 72°F, Low 54°F
- July: High 76°F, Low 57°F
- August: High 77°F, Low 58°F
- September: High 72°F, Low 54°F
- October: High 62°F, Low 47°F
- November: High 52°F, Low 41°F
- December: High 47°F, Low 37°F
Seattle’s summer season (June to September) enjoys conditions above 72°F.
During these months, the daily high temperature peaks at around 77°F in August.
The winter season (November to February) is marked by cooler temperatures, with averages between 47°F to 50°F for daily highs.
In Seattle, nights remain relatively moderate year-round, rarely dropping below 70°F even during summer.
Hot days are rare, with temperatures above 90°F occurring only about four times a year.
For more details on temperature trends, check out this temperature article.
Average Precipitation in Seattle, Washington
Seattle is known for its wet climate, with consistent rainfall throughout the year. While snow is less frequent, it still plays a role in the city’s weather pattern.
Average Rainfall in Seattle, Washington
Seattle experiences frequent rain, with an average yearly precipitation of about 37 inches.
The wettest month is typically December, seeing around 5.4 inches of rain spread over many rainy days.
On the other hand, July is usually the driest month, with about 0.7 inches of rainfall.
Rain in Seattle often comes as light rain or drizzle, contributing to the city’s many days of wet weather.
It is common for Seattle to experience around 150 days of some form of precipitation each year.
Average Snow in Seattle, Washington
Snowfall in Seattle is less common than rain but can occur during the winter months.
The average annual snowfall is about 5 inches, with most of it falling in January and February.
Snow events can lead to icy conditions and can impact transportation and daily life.
While heavy snow is rare, light snowfalls occur a few times each season, turning the city into a winter wonderland.
For more detailed information on Seattle’s winter weather and the impact of snow, you can visit this snow and ice resource.
Average Sun in Seattle, Washington
Seattle experiences a mix of clear and cloudy days throughout the year. The city receives sunlight for a decent portion of the day, but the number of sunny days varies.
Average Daily Shortwave Solar Energy in Seattle, Washington
Seattle gets around 1922 hours of sunlight annually. This means the sun’s rays reach the ground during 43% of the daylight hours.
On average, the city enjoys about 12 hours and 14 minutes of daylight each day.
However, the number of clear skies tends to fluctuate. Typically, Seattle sees sunny skies on around 71 days each year.
To explore more detailed climate information, you can also refer to Seattle weather averages.
Average Humidity in Seattle, Washington
Seattle experiences varied humidity levels throughout the year. On average, Seattle’s relative humidity hovers around 73% annually.
December is typically the most humid month, with average relative humidity reaching 80%.
On the other hand, July stands out as the least humid month with levels around 65%.
| Month | Average Humidity |
|---|---|
| January | 78% |
| February | 74% |
| March | 75% |
| April | 73% |
| May | 69% |
| June | 67% |
| July | 65% |
| August | 67% |
| September | 70% |
| October | 76% |
| November | 79% |
| December | 80% |
The climate in Seattle greatly influences cloud cover.
Overcast days are common, especially during the fall and winter months. High humidity levels in these seasons contribute to the city’s reputation for wet and cloudy weather.
During the summer months, despite lower humidity, cloud cover can still be present due to the marine influence.
The Pacific Ocean’s proximity ensures mild temperatures and consistent moisture in the air, even during the dry season.
Average Wind in Seattle, Washington
Seattle experiences a variety of wind conditions throughout the year. Understanding these patterns can help residents and visitors prepare for different activities.
The average wind speed in Seattle varies monthly.
January is typically the windiest month, with winds reaching their highest speeds.
Conversely, September observes the least wind, making it one of the calmest months of the year.
| Month | Wind Speed (mph) |
|---|---|
| January | 9 |
| February | 8.5 |
| March | 8 |
| April | 7.5 |
| May | 7 |
| June | 6.5 |
| July | 6 |
| August | 5.5 |
| September | 5 |
| October | 6 |
| November | 7 |
| December | 8.5 |
Seattle experiences significant wind consistency, which varies each month.
The average year-round wind speed usually remains below 10 mph. Visitors and locals planning outdoor events can refer to this data to select the best months.
For those interested in wind trends, articles about wind may provide further insights into general wind patterns.
Average Air Quality in Seattle, Washington
Seattle’s air quality has been closely monitored over the years, with varying results. While the city’s air quality is generally acceptable, there are average pollution days that residents should be aware of.
On average, Seattle experiences around 14.2 unhealthy pollution days annually.
These include 7 days due to high ozone levels and 7.2 days due to elevated PM2.5 levels.
This means that while most days are safe, there are still periods when air quality can be concerning.
Key Pollutants:
- Ozone: Often peaks during the warmer months.
- PM2.5: Fine particulate matter that can be harmful when levels are high.
Seattle’s air quality data is available in real-time from various monitoring stations around the city.
Reports and visual maps can be accessed through sources like the IQAir and AQICN.
For those sensitive to air quality, it’s useful to keep an eye on such data, especially during seasons when pollutants are more likely to be higher.
Real-Time Monitoring Stations in Seattle:
- GAIA monitors using laser particle sensors.
- Local stations like Duwamish and others providing hourly updates.
Topography of Seattle, Washington
Seattle, Washington, sits on a narrow strip of land between Puget Sound and Lake Washington. The city’s landscape is shaped by its unique positioning between these two major water bodies.
Seattle’s elevation ranges from sea level to about 520 feet, giving it varied terrain.
Notable Areas:
- Puget Sound: This large inlet of the Pacific Ocean has many islands and peninsulas, contributing to Seattle’s jagged coastline.
- Lake Washington: On the eastern side, this freshwater lake is a significant feature in Seattle’s geography.
Seattle also has several hills. Notably, Capitol Hill and Beacon Hill rise steeply, creating a rolling landscape throughout the city.
Mountains Nearby:
- Olympic National Park: Located to the west, this park features the Olympic Mountains, which can be seen from Seattle on clear days.
- Cascades: The Cascade Range lies to the east, with mountains that often have snow-capped peaks, influencing Seattle’s weather.
The city is covered by a Köppen climate classification type, which further shapes its topography and climate interaction.
Seattle’s varied terrain, with its hills, water bodies, and nearby mountains, makes it a region of diverse and scenic landscapes.
Extreme Weather Events that Occur in Seattle, Washington
Seattle experiences a range of extreme weather events that can make its climate quite unique.
Heat waves are notable in the region. In June 2021, Seattle recorded an all-time high temperature of 108°F. Such stifling heat is unusual but has become more common in recent years.
Freezing temperatures can also hit the city. The coldest temperature ever recorded in Seattle was 0°F in January 1950. Winters can be harsh and bring freezing conditions that challenge residents.
Another significant weather event is heavy rainfall. Seattle is known for its rain, but sometimes the city experiences record-breaking amounts. For example, 0.81 inches of rain fell on September 18, 2021, setting a new record for that day.
During winter months, Seattle can see periods of extreme cold. January, often the coldest month, brings temperatures that frequently drop below freezing. Such cold spells can disrupt daily life and lead to icy conditions on roads.
List of Extreme Weather Events:
- June 28, 2021: Record high of 108°F.
- January 31, 1950: Record low of 0°F.
- September 18, 2021: 0.81 inches of rain, breaking daily record.
Table: Extreme Weather Stats
| Event | Date | Temperature/Rainfall |
|---|---|---|
| Record High | June 28, 2021 | 108°F |
| Record Low | January 31, 1950 | 0°F |
| Record Rainfall | September 18, 2021 | 0.81 inches |
These extremes show the varied and sometimes unpredictable nature of Seattle’s weather. The city’s climate features both searing heat waves and biting cold winters. The data underscores how residents need to be prepared for a wide range of conditions throughout the year.
Best Time of the Year to Visit Seattle, Washington
The climate in Seattle varies by season, making each part of the year unique. Here is an overview of what to expect throughout the year, including typical weather conditions and activities.
What Is Seattle, Washington Like in Spring
Spring in Seattle runs from March to May.
Temperatures begin to warm up, ranging from the mid-40s°F in March to the low 60s°F by May.
Rain is still common, with April seeing about 3 inches.
Spring is a great time to visit for those looking to avoid summer crowds.
The cherry blossoms in full bloom at the University of Washington campus are a highlight.
Outdoor activities, such as hiking in nearby parks and visiting Pike Place Market, are enjoyable as temperatures rise and days grow longer.
What Is Seattle, Washington Like in Summer
Summer, spanning June to August, is the warmest and driest season in Seattle.
Temperatures range from the highs of 70s°F to low 80s°F in July and August.
Rainfall is minimal, with July seeing only about 1 inch.
This season attracts the most tourists, making it the peak travel period.
Popular activities include exploring the iconic Space Needle, enjoying a ferry ride across Puget Sound, and attending outdoor festivals.
The pleasant weather also makes it an excellent time for day trips to nearby mountains and national parks.
What Is Seattle, Washington Like in Fall
Fall in Seattle, from September to November, sees temperatures drop from the mid-60s°F in September to the mid-40s°F by November.
September and October are particularly pleasant, with moderate rainfall and beautiful autumn colors.
This season offers a quieter experience as the summer crowds thin out.
Visiting local coffee shops, exploring museums, and enjoying the fall foliage at places like Discovery Park are popular activities.
The weather remains agreeable for outdoor activities, albeit cooler and wetter as the season progresses.
What Is Seattle, Washington Like in Winter
Winter, from December to February, is the coldest and wettest season.
Temperatures typically range from the high 30s°F to the mid-40s°F.
December and January see substantial rainfall, averaging about 5 inches per month.
Despite the dreary weather, winter in Seattle has its charm.
The holiday lights downtown and events like the Seattle Winterfest attract visitors.
Indoor attractions, such as the Museum of Pop Culture and the Seattle Art Museum, provide great escapes from the rain.
This season is also known for shorter days, with daylight dwindling to around 8 hours in December.