Brook trout will spawn during the fall. Generally, their spawning period is sometime between September and November, when water temperatures are between 42 and 52F.
Most brown trout populations will spawn between September and December, as their eggs and juveniles need plenty of cold, oxygenated water to survive. Their optimal spawning temperature is between 43 and 53F (5 and 12C).
While the average size of rainbow trout is 15 to 25 inches and 1 to 5lb, this trout species can reach a maximum size of around 40 inches and 35-40lb. Some genetically altered stocks can even produce fish that weigh close to 50lb.