When is day-time for the purpose of vampirism(‘s Weakness to Sunlight)

the-elder-scrolls-v-skyrim

While outside during the day, health, magicka, and stamina are reduced, and the regeneration for each of these stats is reduced by 100%. The reduction increases with each stage of vampirism.

http://www.uesp.net/wiki/Skyrim:Vampirism#Weakness_to_Sunlight

What time has sunlight?

Best Answer

Day begins at 5am and ends at 7pm regardless of weather or the visibility of the sun.

http://www.uesp.net/wiki/Skyrim:Vampirism#Weakness_to_Sunlight

That makes 14 hours of sunlight; 10 hours of night-time.