Federal Center South Building 1202
SENV 7006
Climate Analysis
Seattle's climate is classified as oceanic or temperate marine, with cool, wet winters and warm, relatively dry summers. Most of time, compared with the 15℃ average low temperature, theaverage high temperature in the summer is not more than 30℃, which means the temperature in the summer make people comfortable.
Winters are cool and wet with December, the coolest month, averaging 4.8 °C, with 28 annual days with lows that reach the freezing mark.
Temperature
Seattle experiences its heaviest rainfall during the months of November, December and January, receiving roughly half of its annual rainfall during this period. Conversely, the city receives some of the lowest precipitation amounts of any large city from June to September. Besides, Seattle typically receives some snowfall on an annual basis but heavy snow is rare. And Seattle is one of the five rainiest major U.S. cities as measured by the number of days with precipitation, and it receives some of the lowest amounts of annual sunshine among major cities in the lower 48 states. The figure shows that the sunshine duration in winter is only 2-4hours, and even in summer time, the sunshine duration is also lower than 10 hours.
Rainfall & Radiation
Temperature Chart
As we can see from these two graphs, the prevailing wind direction in Seattle is north and southwester wind, the hours of wind which is from these two directions accounts for about 50%, and the ordinary wind power is also strong and powerful. For more details, the highest speed of the wind is more than 14m/s, and the annual speed is about 4m/s. We can see the data from the figure, the speed of wind is extremely stable and soft and the buildings are influenced by continuing wind frequently. Besides, talking about the humidity of the wind, due to the special climate and location, the average humidity of wind from southern and northeastern area is always higher than 70%. And the wind in other direction is also high than 30%. Besides, it is clear to find the temperature of the wind, the annual temperature of the wind is lower than 22℃, and the wind from eastern area is cooler than it from western area.
These two figures are the sun shading charts. The left one is the sun shading from December to June, the results are all the blue, which means during these time, and we need more sun to provide to people. And as for the figure from June to December, the result shows that the period from July to August is the comfort zone. But before July, there need more shading device to protect from much more sun. After August, the result is as same as figure from December to June, thus we need more sun to provide to people.
Wind
According to the data, because there is much more rain in the winter period, the humidity in winter is high. For instance, the average humidity in January and December is higher than 80%, which could make people feel uncomfortable and moist. On the contrary, the average humidity in summer time is lower than winter. But, the humidity is also higher than 60%, sometimes it will increases to 80%. However, in the middle time of summer period, the relative humidity is about 50%, which conforms to the comfortable environment.
Depending on the psychrometric chart, there are 16 ways to enlarge the scale of the comfort zone. And only 6 of them can make a great contribution to enlarge the comfort zone. As we can see, the best way is heating and internal heating gain. Just like the introduction before, Seattle is a warm and comfortable city in summer and the temperature would not be higher than 30℃. However, the winter is cold and wet, the temperature in January and December is lower than 0℃. Using the heating system properly and efficiently can enhance evaporation and improve the comfort directly. Besides, the passive solar gain is also good choice. The annual sunshine of Seattle has lowest amounts among major cities in the lower 48 states, which enforce the gain of sunshine and heating.
Sun Shading
Humidity & Psychrometric Chart
Rainfall Chart
Sunshine Duration Chart
Wind Wheel Chart
Wind Velocity Chart
Sun Shading Chart(June-Dec)
Sun Shading Chart(Dec-June)
Psychrometric Chart
Relative Humidity Chart
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