THE CALENDAR PERIODS

The In-Fisherman Calendar divides the fishing year into 10 periods of fish response. These Calendar Periods are at the mercy of Mother Nature, so they don’t last a certain number of days, nor do they occur on specific dates each year. Since Calendar Periods depend on climate and water conditions, they will vary in length from year to year depending on weather trends. Calendar Periods which might last a few days one year could last several weeks the next year.

Calendar Periods vary according to regions. In areas of Canada, the Summer Calendar Period might arrive in July and last a few weeks. Meanwhile in Florida, the Summer Period may arrive in May and last for 5 months.

The Prespawn, Spawn and Postspawn Periods relate primarily to reproduction. Periods like the Summer, Fall (Cold Water), and Winter (Coldest Water) Periods relate more to water temperature and seasonal conditions.

Learn to read the sign’s, and you’ll be able to identify one period from another and to determine when various species are in different Calendar Periods. Recognizing seasonal movements and fish response patterns is important to fishing success.

FISH ACTIVITY DURING THE 10 CALENDAR PERIODS

Prespawn: The period when fish are on the way to, or in the vicinity of, their spawning areas prior to spawning. During this stage, there can be feeding activity and heavy grouping. Fishing can be good.

Spawn: A brief, variable period linked to the range of preferred spawning temperatures for each fish species. Feeding activity is minimal. Fish of the same species do not always spawn at the same time, however.

Postspawn: The length of the Postspawn Period is variable, depending on water conditions, species of fish, and the sex of the fish. Male fish tend to be more responsive to fishing.

Presummer: A transition period during which fish begin to establish summer patterns.

Summer Peak: During this short period most fish of a species establish summer patterns. The Summer Peak often begins after several days and nights of hot weather. Competition for abundant food spurs fish activity and good fishing.

Summer: Fish may stick to location patterns established during the Summer Peak. Algae blooms, cold fronts, abundant forage, and other factors may make fishing difficult. Fish activity patterns and fish location are predictable, however.

Postsummer: This period occurs at the end of summer when days and nights bring consistently cooler weather. Fishing often is good.

Fall Turnover: A short period when the lake is in turmoil from mixing of cold surface water and warmer water below. Turnover homogenizes lakes that have thermoclined (layered accordingto water temperature) in summer. Fishing is usually poor.

Cold Water: This period occurs twice, once in early spring and again during late fall. Fish establish specific patterns. Fishing can be very good.

Winter: This is the coldest water of the year. Frozen water is common in northern regions.


While Calendar Periods always occur in order, their length varies for each species based on such things as geography and body of water type. The periods are not the same for each species. Largemouth bass, for example, are often in the Spawn Period when pike are in the Presummer or Summer Peak Period.

Calendar Periods are important because they pinpoint where fish are located and how active they are.