Returns forecasts and other information for univariate Holt-Winters time series models.

```
# S3 method for HoltWinters
forecast(
object,
h = ifelse(frequency(object$x) > 1, 2 * frequency(object$x), 10),
level = c(80, 95),
fan = FALSE,
lambda = NULL,
biasadj = NULL,
...
)
```

object

An object of class "`HoltWinters`

". Usually the result of
a call to `HoltWinters`

.

h

Number of periods for forecasting

level

Confidence level for prediction intervals.

fan

If TRUE, level is set to seq(51,99,by=3). This is suitable for fan plots.

lambda

Box-Cox transformation parameter. If `lambda="auto"`

,
then a transformation is automatically selected using `BoxCox.lambda`

.
The transformation is ignored if NULL. Otherwise,
data transformed before model is estimated.

biasadj

Use adjusted back-transformed mean for Box-Cox transformations. If transformed data is used to produce forecasts and fitted values, a regular back transformation will result in median forecasts. If biasadj is TRUE, an adjustment will be made to produce mean forecasts and fitted values.

...

Other arguments.

An object of class "`forecast`

".

The function `summary`

is used to obtain and print a summary of the
results, while the function `plot`

produces a plot of the forecasts and
prediction intervals.

The generic accessor functions `fitted.values`

and `residuals`

extract useful features of the value returned by
`forecast.HoltWinters`

.

An object of class `"forecast"`

is a list containing at least the
following elements:

A list containing information about the fitted model

The name of the forecasting method as a character string

Point forecasts as a time series

Lower limits for prediction intervals

Upper limits for prediction intervals

The confidence values associated with the prediction intervals

The original time series
(either `object`

itself or the time series used to create the model
stored as `object`

).

Residuals from the fitted model.

Fitted values (one-step forecasts)

This function calls `predict.HoltWinters`

and constructs
an object of class "`forecast`

" from the results.

It is included for completeness, but the `ets`

is recommended
for use instead of `HoltWinters`

.

# NOT RUN { fit <- HoltWinters(WWWusage,gamma=FALSE) plot(forecast(fit)) # }