On July 4, 1981 in Washington, DC, it rained until 12:30 pm and the temperature at 2 pm was 75 degrees, which is pretty cool for DC in July. Not freezing, however.
but if your used to Maryland high humidity and the 80s/90s (think wool, plebe summer in Annapolis) and then got drenched in the rain in the 70s I could see how some boys would be huddling-up, shivering.