Sansa Appreciation Week: [Day 4] Favorite Relationship → Sansa & Arya
∟ You may be as different as the sun and the moon, but the same blood flows through both your hearts. You need her, as she needs you.
In addition to the color theory reasons, GoT recently explained the in-character reason why Dany wears blue all the time. Source: Costume Designer Michele Clapton, via the S3 Blu-Ray special features.
"Blue was the color of royalty in Khal Drogo’s khalasar. It was the color of the expensive dye which they adorned themselves with, more so on special occasions such as Drogo’s wedding. […] Thus, while in Season 3 Daenerys no longer wears a Dothraki-style "cut" to her outfit, she switched to blue colors as a symbol of her authority as a Khaleesi and in memory of Drogo."