There is a year-round burn ban in Duval County. As for fireworks, the temperature outside isn’t a legal consideration but you should exercise caution because when it’s dry outside it’s easier for a fire to start. According to Florida State Statute 791, fireworks must be in the form of a sparkler or something that sits on the ground and can be lit. If it leaves the ground and/or explodes in the air it’s illegal to light in Florida.