Forecasts

A line tells what happened. A forecast extends it: a few more months, quarters or days, drawn in green dashes, over an area marked “Forecast”, with the range within which what comes next is likely to fall.

Extending a trend

In the Visualization panel, Forecast section: Extend the trend by N periods — +3, +6 or +12 in one click, up to 36.

What you need
A chart type	Lines, Areas, Bars or Combo
An axis	a date grouped by day, week, month, quarter or year
Data	at least 3 periods

Forecast periods are added to the axis. The tooltip flags them (“forecast”) and clicking one of them filters nothing: it has no rows yet.

The drawing

One series: the forecast takes insights green, in dashes; forecast bars have a dashed outline and a light fill.
The 80% interval surrounds a single forecast with a green band that widens with the horizon: the further ahead you look, the more uncertain what comes next. It can be hidden with a setting.
Several series: each forecast keeps the color of its series, in dashes — otherwise you could no longer tell which forecast extends which line; they are not added to the legend.
A series that is always positive (sales, visits) is never forecast below zero.

Methods

Method	What it does	When
Automatic	chooses among the three below	by default
Seasonal (additive Holt-Winters)	a trend and a repeating pattern: 12 months, 4 quarters, 7 days	as soon as the series covers two seasons
Smoothed (Holt)	a trend that follows the latest movements	from 6 points
Linear (least squares)	the straight line that passes closest to the points	otherwise

Smoothing parameters are chosen by minimizing the one-step-ahead forecast error on the series itself; the interval comes from that same error. The calculation is done in the browser, on the displayed result: it doesn’t rerun any query and sees only what you see.

Wherever your charts are

Forecasts can be set on a question as well as on a dashboard card, and the MCP server draws them in Claude too: see MCP.

eodia insights is free software by Eodia.