When it comes to being a guest at a wedding, you can wear anything you would like, although some things may be considered more appropriate than others. Wearing a dress is a good choice, since most weddings are formal occasions. Wearing a light blue color should be appropriate, as the generally accepted rule for guests attending a wedding is that women and girls not wear white, so as to not distract from the bride's dress. Finally, although solid black is not a color that is traditionally worn at weddings, it should be appropriate to wear a black sweater with your dress, since it can easily be removed during the reception. Again, the main goal for guests attending a wedding is not to distract from the bride with their outfits, and a guest wearing a light blue dress with a black sweater would most likely not be breaking that rule.

On the Other: Consider the Feelings of the Bride and Groom

While a light blue dress should be appropriate for a wedding, a black sweater may not be, since black is traditionally seen as a color of mourning. Although black is becoming increasingly more acceptable at weddings, the bride, the groom or their families may be very traditional, and such a wardrobe choice could be taken as an affront. It is best to consider the feelings of the bride and groom, and to be safe, you might want to avoid wearing black to a wedding.

Bottom Line

Overall, since only the sweater is black and can easily be removed during the reception, it should be an appropriate accessory to wear with a light blue dress, especially since the color of the sweater will be offset by the cheerful tone of the dress.

Source:

Style Chefs: Wearing White to a Wedding

Stealing Attention from the Bride

Guide for Guests: Wearing Black to a Wedding