Live by the cloud, die by the cloud. Ok, life as a photographer isn't that dramatic, but knowing what the sky is going to do is great information to have. Clear Dark Sky gives you that information and more.
Although designed for astronomers, Clear Dark Sky is equally useful to any photographer who work outdoors, particularly those who work with natural light or astrophotographers. Its interface is very simple; just enter your location and select the chart location you'd like to use. You'll be presented with a chart like this:"Cloud Cover" is just that, with grays and whites corresponding to varying levels of overcast skies, and darker blues corresponding to clear skies. "Transparency" measures how water vapor in the air affects the ability to see space objects. "Seeing" measures how air turbulence affects the ability to resolve fine details of objects in the sky. "Darkness" tells how dark the sky will be at that time; it takes into account the sun and moon, but does not consider light pollution. I've used Clear Dark Sky's charts before and have found the cloud forecast to be quite accurate both during the day and night. The more astronomically oriented parameters are quite accurate and helpful as well. Try it out here.
Another useful FREE tool: http://suncalc.net/
I hadn't thought about using it for daylight photography. I don't do astronomy; for seeing if the weather's clear for watching the Space Station fly over, I just walk outside. I did have a year long project of photographing the full moons; but I set up during cloudy weather and hoped for breaks in the clouds. With rain, I was skunked and had to postpose for the next day.
Agreed. Been using it for years and it's been fairly accurate - certainly more accurate, or at least more specific, than the standard weather sources.
I've been using https://sunsetwx.com for sunsets and sunrise. It's pretty accurate.
With all do respect, but this is kind a joke. There are many awesome sites (and yeah they include other continents like Europe, Asia, Africa, etc.), I am not sure why to use this "thing". For accurate weather forecast including damn good cloud cover and rain forecast in hours, yes in hours : https://www.wunderground.com/ or http://www.yr.no/ . For real time cloud cover I like this one and it's creepy accurate: http://www.wetteronline.at Soo...thanks, but no thanks.
P.S. Thumb up for the Suncalc Jon.
With all due respect, I use it both because it's more accurate than Weather Underground and because it offers parameters uniquely related to astronomy and photography that no other site readily does.
No disrespect to you Alex, sorry if it sounds like that. It's just that I am not super impressed with the site, sorry that's my subjective opinion.