Sunrise and Daylight?

[Ray Young]

I was wondering if anyone knows how long before the official sunrise time at this time of year will you get useable light for offroad cycling purposes?

[mountainbaker]

As soon as you can see where you are going?!

[Ray Young]

As soon as you can see where you are going?!

Seriously, I need to know what time to set my alarm to get maximum daylight riding hours.

[Bearbonesnorm]

It's about half six at the moment but the weather makes a massive difference too ... it didn't really get light here this morning until gone 8. The official sunrise time on Nov 1st is 7.15am for Northern England.

[Chew]

As usual it depends....

As a general rule it will start to get light 30 mins before the official sunrise time. (There will be some fancy name for it, but it's the sun reflecting off the atmosphere before it rises above the horizon)

If it's a clear sky and your in the open that will be at the early end of that scale, overcast and in the forest it will be on the later side.

[ScotRoutes]

Very much depends on cloud cover.

[Ray Young]

OK, thanks. Think I will set the alarm for an hour before sunrise on the first day then see how I get on.

[VeganGraham]

Isn't this something that would be best found out by experiment? After all, your idea of enough light might not match everyone else's.
Another thing to bear in mind is that the sun doesn't always rise and set at the same angle.
The angle is steepest at the equinoxes, giving shorter twilight, and shallower at the solstices, giving longer twilight.

[Ian]

Depends on the type of trail too. It's possible to ride fireroad long after the sun has gone down or has yet to come up, but as soon as you hit something technical or go through some trees, it all changes.

[ir_bandito]

http://www.thetimeandplace.info/suntimes/uk

[jameso]

I was riding at 6am on a clear-sky morning the other weekend with lights, turned them off at maybe 6.35-6.45 but as Ian said, between tree cover and open trail makes all the difference. And for alarms, so does how fast you can make a brew / pack up etc : )

[VeganGraham]

Another thing to take in to account if you are working from published sunrise times, assuming you are in the UK and my calculation is correct, is that for every 16km West of Greenwich you are, the sun will rise 1 minute later.

[Ray Young]

And I thought I was asking a simple question. Lots of variables to take into account that I had never thought of. Thanks for all the input.
This mornings departure was delayed by thick freezing fog, couldn't see more than a few feet so I opted to stay in the bothy for a wee while longer.