Trends/Relative strength, cycles and structure

Monthly seasonality

The stock's average return in each calendar month over past years.

Relative strength, cycles and structureBest on 3Y, 5Y, MAXAlso called calendar month returns

Illustration of the monthly seasonality shape. It is a sketch, not real price data.

What it shows

Seasonality groups past returns by calendar month. For each month, it shows the average return and the share of years that were positive.

Some months have been stronger than others in the past. It does not say the pattern will repeat, and with 10 or 20 years of data each month has only 10 or 20 observations.

How we find it

The same code that draws it on your chart follows these steps, with the same result every time.

Compute each month's return for each year.
Average by calendar month.
Count the share of positive years.
Show as bars.

Starting values: Years up to 20. These are proposed and will be tuned on real price data before launch.

How to read it

Each bar is a month's average return.
Teal bars were positive, red negative.
The dashed line is zero.

Status labels you may see

Label	What it means
Historically strong month	Positive in 70% or more of years.
Historically weak month	Positive in 30% or fewer.
Mixed	In between.

What cancels it

Nothing cancels it.

What traders check next

Number of years.
Variation between years.
Outliers.

Limits

Small sample per month.
Patterns may be by chance.
Averages hide big year-to-year differences.

Try it in forecastviz

Open any ticker and choose Relative strength, cycles and structure → Monthly seasonality in the left menu.
Switch between 3Y, 5Y, MAX to see how the picture changes.
Compare with Day-of-week effect and Turn-of-month effect on the same chart.

Open on a ticker

Questions

Is 'sell in May' true?

In some markets and periods it was. We make no claim for the future.

How many years do I need?

Many. Even then, it can be noise.