SEATTLE — As autumn approaches, Seattle residents brace for the upcoming ‘Big Dark,’ marking the gradual loss of daylight that will continue until early 2026.
The last 7 PM sunset will occur on September 25, with the last 6 PM sunset following on October 26. The first sunset before 5 PM will be on November 2, coinciding with the end of Daylight Saving Time.
In the Northern Hemisphere, the Earth begins to tilt away from the sun after the summer solstice in June. In Washington, daylight hours decrease significantly this time of year, with the state losing around 50 minutes of daylight in July alone. However, the months of August through October bring a more rapid descent into darkness, with a loss of 80 to 90 minutes in August, followed by 90 to 100 minutes in both September and October.
Even though November experiences a smaller loss of around 70 minutes of daylight, the psychological impact can be more pronounced due to the time change, which results in earlier sunsets before 5 PM.
The sunlight cycle shifts once the winter solstice hits in December, as the Earth begins its tilt back toward the sun, signaling a gradual gain in daylight.
Washington experiences some of the most significant changes in daylight due to its northern latitude. The dramatic shifts in light can be attributed to the combination of the tilt of the Earth’s axis and its yearly revolution around the sun, contributing to extreme seasonal variations.
Here’s a look at how daylight will diminish as we approach the winter solstice, month by month:
By September 1, the sun rises at 6:28 am and sets at 7:48 pm, creating a daylength of 13 hours and 20 minutes, with a daily loss of 3 minutes and 18 seconds of daylight.
The fall equinox arrives on September 22, with sunrise at 6:56 am, sunset at 7:06 pm, and a total daylength of 12 hours and 9 minutes. This equates to a daily loss of 3 minutes and 24 seconds of sunlight.
Moving into October, on the 1st, sunrise occurs at 7:09 am, and sunset will be at 6:47 pm, yielding 11 hours and 39 minutes of daylight, which results in another daily loss of 3 minutes and 24 seconds.
By November 1, the sun will rise at 7:54 am and set at 5:51 pm, resulting in 9 hours and 57 minutes of daylight, with a daily reduction of 3 minutes and 4 seconds.
With the end of Daylight Saving Time on November 2, sunrise is at 6:55 am, and sunset drops to 4:49 pm, contributing only 9 hours and 54 minutes of daylight and leading to a loss of 3 minutes and 2 seconds.
On December 1, sunrise will be at 7:37 am, and sunset will occur at 4:19 pm, reducing daylength to 8 hours and 42 minutes, with even less daylight lost this time at only 1 minute and 41 seconds.
Finally, the winter solstice hits on December 21, with sunrise at 7:55 am and sunset at 4:20 pm, giving a daylength of 8 hours and 25 minutes, effectively losing just 1 second of daylight.
In terms of weather, the Pacific Northwest can expect some showers this Sunday as a weakening front approaches.
As high pressure shifts eastward, a front will bring rain late Saturday into early Sunday, resulting in a cloudy morning with potential convergence from King County northward throughout the afternoon. Rainfall may reach up to an inch along the coast, while inland areas may receive less than a quarter-inch, although some localized zones undergo heavier precipitation.
While a few showers may linger into Monday morning, expect clearer skies and partly sunny conditions by the afternoon as high pressure resumes its influence.
Temperatures are likely to warm significantly on Tuesday, with highs in the low to mid-80s as a thermal trough moves into the region. However, the forecast indicates a chance of showers mid-week as another weather system rolls in.
image source from：king5
