Code of Massachusetts Regulations
520 CMR - DEPARTMENT OF PUBLIC SAFETY
Title 520 CMR 13.00 - The Operation Of Horse Drawn Carriages For Public Hire On Public Roads And Ways On The Commonwealth To Ensure Public Safety
Section 13.10 - Carriage and Horse Operations Prohibited During Adverse Weather Conditions, Detrimental to Public Safety

(1) Horse Drawn Carriages shall not be driven during adverse weather conditions, which shall include, but not be restricted to snow, ice, heavy rain, slippery conditions or extreme cold, heat or humidity.

(2) Horses shall not be worked in temperatures over 90°F or below 18°F according to the U.S. Weather Bureau; or if, in the opinion of an Inspector, it appears that a horse is in danger because of extreme temperature.