24th
During morning meeting, I fondly recalled there being light outside until 9:30 or 10:00 PM during the summer in Washington State. Carwai wasn’t buying my numbers, but it wasn’t a good time to debate. Then, with a little doubt nagging at me all day, I decided to do a little research…
What you see above is the chart of darkness (grey), dawn (blue), sunshine (yellow), and dusk (pink) in Bellingham, Washington over the course of a year. The Roman numerals are the months of the year and the numbers on the right are the time of day using a 24-hour clock. As you can see, it does stay light until 10:00 PM (22:00) during the longest day of the year, the summer solstice, which occurs around June 21 each year. Remember that I said the longest day of the year was about a month away?
So, why might Carwai not think that there could be light at such an hour? Well, if you look at the same type of chart for Halifax, Nova Scotia, Canada, you’ll see that dusk ends there around 9:30 PM (21:30) during summer solstice. But isn’t Canada north of the contiguous US? Yes and no. Most of it is, but not all of it. Halifax is located at 44°51′16″N 63°11′57″W. Bellingham is located at 48°45′1″N 122°28′30″W. That’s significantly farther north and it accounts for the difference in the length of the day.
Glad to sort that out. :) Let me know if you have any questions.
