"Indeed, a slightly salacious folklore grew up around the New England winter, associating it with sexual activity which might anticipate marriage. Esther Burr, writing to a friend in 1755, noted the boom in winter weddings and provided a compelling if unorthodox explanation. "Pray what do you think everybody marries in or about winter for: 'tis quite merry, isn't it? I really believe 'tis fear of laying cold, and for want of a bedfellow." Almanac writers marked November, December, and January as a season of short days and long nights, to be spent in the pleasure of meat, drink, warm fires, and close company."
David Cressy. The Seasonality of Marriage in Old and New England from The Journal of Interdisciplinary History, Vol. 16, No. 1 (Summer, 1985), pp. 1-21
The most popular season for weddings in 17th and 18th century New England was in late fall/winter (peaking in November and December). There were very few weddings in the summer because New England weddings followed the agrarian calendar and from July-September, New Englanders were hard at work harvesting grain and corn. Late fall/winter on the other hand was a good time to get married because there was a surplus of food, and lots of time to kill.
Boston didn't follow the same wedding pattern as the rest of New England because it was relatively independent from the agrarian calendar (as it had many more forms of industry); allowing weddings to be more evenly distributed throughout the year.
Take a look at a wedding dress from Bostonian Elizabeth Bull from 1730. Bull was 14 when she stitched the dress.