You won't hurt anything by taking a peek. Cold cider is sometimes a slow start for activity, especially if you pitched dry yeast instead of a starter. You may want to bring it inside for a day to warm up and get the yeast going, then move it back to cool down. Cider does benefit from a cool, slow fermentation. Additionally, the addition of sugar to a sweet juice may have created a slightly high OG that is also slowing the yeast.