How should I dress?

Comfortably! You'll be outdoors for a while so dress appropriately and note that weather in Boston is not easy to predict. Temperatures can swing over ten degrees during a tour and the weather on one side of the city doesn't always indicate what's happening on the other side, especially near the harbor where each intersection has its own weather system. Err on the side of bringing the coat, extra layer or umbrella if you're wondering if it will be needed.

You can check the tour calendar for the 10 day weather forecast.