SWAMPSCOTT – Forest Avenue is shady under a canopy of tree branches, but by 10 a.m. Thursday Swampscott town employee John Gillette and his fellow workers were sweat-drenched as they patched the street with hot asphalt.”The heat is tough. You drink a gallon of water a day but you have got to move out the work,” said Gillette.With six years experience as a town Department of Public Works employee, Gillette knows the department – like many other DPW departments in other communities – has to take advantage of summer weather to repair and patch local roadways.Asphalt batching plants open in April, and spring rains and cooling fall temperatures can narrow the work window available for workers like Gillette, John Murphy and Bruce Conley to do the hot, hard work of filling potholes and patching damaged streets.Even on the hottest days, like Thursday, when temperatures hit 90 degrees, Gillette and coworkers spread asphalt heated to 325 degrees across Forest Avenue and other roads around town. Gillette and Murphy wore long pants but veteran DPW employee Conley opted for shorts.”I’m all about comfort. Heat goes with the territory on the job, but you have to pace yourself,” Conley said.After winter’s unrelenting deep freeze and deep snow, Conley is savoring a hot summer. Longtime construction worker and new town employee Murphy also prefers working in hot weather over cold.He drinks plenty of fluids during the work day and makes sure he eats enough food to give his body energy to work and stay cool.”I try to keep a positive mind set. If you’re lucky, you find a nice shady spot to work in,” he said.The Massachusetts Public Health Department cites the Center for Disease Control in underscoring extreme heat as the top killer among causes of death not caused by humans.Heat paired with humidity can lead to heat stroke, exhaustion, cramps and heat rashes.Federal work safety guidelines recommend employees who must work outdoor do so, if possible, during cooler parts of the day and dress in lightweight, light-colored clothing capable of blocking out the sun’s rays.Workers should plan to take rest breaks and drink water frequently. Federal guidelines also recommend outdoor workers not work alone so that coworkers can quickly respond in case of an emergency.National Grid crews working in the noontime sun on Alley Street in Lynn Thursday are allowed, according to utility spokeswoman Danielle Williamson, to not perform any work requiring rubber-sleeved clothing once temperatures hit 90 degrees.”This doesn’t exclude them from doing other types of work, but they are more limited,” Williamson said.Murphy, a Marblehead resident, said the best part of a hot work day is the reward at the end.”I like to go to Little Harbor and jump in the water,” he said.