When does it get dark?

I wish to commute in the evening on Marine Drive in Portland, and I wish to know when is the best time to leave my meeting, when I can still be visible without lights. I went to look up sunset times, and this wasn't very helpful, because there are three different times, civil, nautical, and astromonical twilight. How do I translate this into cycling twilight?

I have been bumming rides to the meetings, but it is important to me to start commuting by bike, to set a 'good example' that a good lifestyle doesn't require driving everywhere.

Thanks,
Mary M

IT's hard to call and I think it is different depending on where you are -- and on your definition of dusk, and how cloudy it is. I'd test it myself to see.
Personally, I would get lights so that no matter what happened, I'd be reasonably safe. (I have a couple of blinkies and a string of Christmas Tree lights wrapped to make a triangle on my backpack that does wonders and doesn't require a lot of thought.)

Cars drive with lights all day here, even in summer when it doesn't get dark at all. And cyclists use flashing lights day and night. Lights help on visibility even if it isn't dark, and then sunset times are one less thing to worry about.

I keep a Sunrise/Sunset chart for my town posted on my fridge. I use it more in the morning as a gauge of when to wake up. I usually get up at Civil Twilight. This way by the time I get dressed, pump up my tires and get out the door it is light enough to ride without lights.
For the evening however, I don't think I would ride past Sunset without lights for others to see me. Civil twilight is for me is the time I can personally last see without compromising my safety.
As others have said however, always go on the side of caution when using your lights.

Does this help?

http://www.timeanddate.com/worldcloc...omy.html?n=202

C

I am getting home around 845pm from a class (Seattle, we have more light than you this time of year) and I have noticed how drastically different the light is when it's cloudy vs sunny. So IT DEPENDS!

The other thing is that dusk is the nastiest time and the least safe; with good lights you're more visible in the dark.