Amazon Forecast is no longer available to new customers. Existing customers of Amazon Forecast can continue to use the service as normal. [Learn more"](https://aws.amazon.com/blogs/machine-learning/transition-your-amazon-forecast-usage-to-amazon-sagemaker-canvas/)

# Retraining Predictors
<a name="retrain-predictors"></a>

**Note**  
Retraining is only available for predictors created with AutoPredictor ([`CreateAutoPredictor`](API_CreateAutoPredictor.md)). You can upgrade existing legacy predictors to AutoPredictor. See [Upgrading to AutoPredictor](howitworks-predictor.md#upgrading-autopredictor).

Predictors can be retained with updated datasets to keep your predictors up to date. When retraining a predictor, Amazon Forecast maintains the same predictor configuration settings. After retraining, the original predictor will remain active and the retrained predictor will have a separate Predictor ARN.

Retraining a predictor can improve forecasting accuracy in two ways:

1. **More current data**: Your retrained predictor will incorporate more up-to-date data when training a model.

1. **Predictor improvements**: Your retrained predictor will incorporate any updates and improvements in the Amazon Forecast algorithms and additional datasets.

Retraining a predictor can be up to 50% faster than creating a new predictor from scratch. Predictor training times are faster and Forecast automatically uses your existing configuration settings.

**Python notebooks**  
For a step-by-step guide on retraining predictors, see [Retraining a predictor](https://github.com/aws-samples/amazon-forecast-samples/blob/main/notebooks/advanced/Retraining_AutoPredictor/Retraining.ipynb).

You can retrain a predictor using the Software Development Kit (SDK) or the Amazon Forecast console.

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#### [ Console ]

**To retrain a predictor**

1. Sign in to the AWS Management Console and open the Amazon Forecast console at [https://console.aws.amazon.com/forecast/](https://console.aws.amazon.com/forecast/).

1. In the navigation pane, choose **Predictors**.

1. Choose the predictor to retrain.

1. In the **Predictor actions** drop-down, choose **Retrain**.

1. Set a unique name for the upgraded predictor.

1. Choose **Retrain predictor**.

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#### [ SDK ]

**To retrain a predictor**

Using the [`CreateAutoPredictor`](API_CreateAutoPredictor.md) operation, assign the predictor a unique name and set the value of `ReferencePredictorArn` to the predictor you wish to retrain.

```
{
  "PredictorName": "RetrainedPredictor",
  "ReferencePredictorArn": "arn:aws:forecast:us-west-2:938097332257:predictor/OriginalPredictor"
}
```

When retraining a predictor, assign values to only the `PredictorName` and `ReferencePredictorArn` parameters.

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