just enter your latitude and the date and this calculator will tell you the day length. http://astro.unl.edu/classaction/animations/coordsmotion/daylighthoursexplorer.html
Had my girls under 18/6 put them out and they are flowering its only June! but according to the chart they are only seeing 15ish hours of day light. Anyone have experience with premature flowering? will they revert back to veg come the summer solstice?