Free tool

Seasonality of your data

Enter twelve monthly values and measure how seasonal you are with Eurostat's indicators: share of the peak months, Gini coefficient and coefficient of variation.

Twelve monthly values are enough to see how concentrated your business is in a few months, with the same indicators Eurostat uses to compare European countries. It works in any country and for any measure: nights, covers, visitors, revenue.

Your values, month by month

Use the same measure and the same year for every month. Zero is a valid value.

Your numbers stay on your device: the calculation runs in the browser and nothing is stored.

Worked example

Nights spent in tourist accommodation in the European Union in 2025 (Eurostat): with these twelve values the Gini is 0.249 and the two peak months account for 31.2% of the year.

How it is calculated

  • Share of the peak months = sum of the two (or three) highest months / total for the year. The peak months are the highest of your own curve, not necessarily July and August.
  • Gini = Σᵢ Σⱼ |xᵢ - xⱼ| / (2 · 12² · mean), without the small-sample correction: this is the form that reproduces the values published by Eurostat.
  • Coefficient of variation = population standard deviation / mean: the twelve months are the whole year, not a sample.
  • Peak: up to three of the highest months, only if they reach at least 1.25 times the monthly average. Empty: below 1/24 of the total, that is less than half of an even month. Shoulder: all the others. No official source defines peak or shoulder months: these thresholds are the Play the Event convention.
  • No moving average and no forecast: the tool describes the year you entered, it does not tell you what will happen.

How it works

Enter one value for each month of the same year: nights, covers, visitors or revenue. Press «Calculate»: the tool shows the share of the two peak months (Eurostat's indicator), the share of the three peak months (the OECD's), the Gini coefficient and the coefficient of variation, and tells you which months are peak, shoulder or empty months.

Next to the result you find the European Union average and, if you want, an Italian province. The calculation runs in your browser: your numbers are neither sent nor stored.

Frequently asked questions

What does the seasonality Gini coefficient measure?

It measures how far the twelve months are from an even distribution: it is 0 when every month has the same value and 0.917 (that is 11/12) when everything falls in a single month. Eurostat uses it to compare countries: for nights spent in tourist accommodation in the European Union in 2025 it publishes 0.25.

Why the share of the two peak months and not just July and August?

Because peak months change from place to place: in a ski resort they are January and February, in the southern hemisphere December and January. Eurostat measures the share of each area's two highest months; the July and August share remains a descriptive figure for the northern hemisphere.

Is my data stored?

No. The calculation runs in your browser and the page does not send your values to any server. If you choose an Italian province for comparison, the page only downloads the public ISTAT file for that province.

Limits of the calculation

  • The indicators describe how your values are distributed: they do not explain the causes and do not forecast next year.
  • Comparing with the European Union and with provinces only makes sense if your values are nights; for covers or revenue, compare your own years with each other.
  • An unusual year (works, closures, pandemic) changes the indicators a lot: compare several years before drawing conclusions.

Sources

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