In photography, the golden hour (sometimes known as the magic hour) is the first and last hour of sunlight during the day. It's usually about 30 minutes before and after sunrise and the same during sunset. The golden hour will be affected by your location and the time of year, but this is a good rule of thumb. There are great apps out there that will tell you when the golden hour will be based on your location. I'm currently using a really simple one called Photo Hour and find it works pretty well. It tells you when the golden hour starts and ends based on you location. This is particularly useful if you want to sleep until the last possible minute while on vacation, but still want to get up in time to catch the sun rise.
Anyway, the quality light you get during the golden isn't always an issue and today was one of those days for me. I'm spending the weekend in El Dorado Hills, CA and wanted to get up this morning to shoot photos of a really cool bridge i saw in nearby Auburn. So, I got up at 4:45 in the morning and made the 30 minute trek to the bridge. I got there all excited because not only was I going to be able to shot some photos, but I was going to be able to use my tripod and neutral density filters (for the water under the bridge) and I love using my stuff. I got there when the sun was just coming over the ridge. That's when I noticed that this bridge was right next to small mountain and that mountain was blocking the sun. So, the shot I wanted, of the first morning light shining off this bridge want going to happen. It still was a nice shot and I'm glad I went, but this just proves how helpful scouting out you location is. If I would have gone to check it out the day before and thought about it, I would have realized that the mountain was going to fully block the sun from hitting the bridge.