I don’t think it’s possible. She traveled from Winterfell to Castle Black, stayed there for an unknown amount of time, and then back down to Winterfell. That’s a little over 1200 miles. I’m pretty sure she would be showing at this point.

You know that Singapore is a city-state, right? Saying, “...with skies so bright over the whole country that no spot of the country was dark enough at night for human eyes to adapt to night vision.” is a bit misleading, even if technically accurate.