StructuredFor DevelopersMachine Learning & AI Engineering

Time Series Forecasting Guide.

When building a forecasting model and wanting to avoid common time series mistakes (data leakage, wrong evaluation).

ChatGPT Β· Claude Β· GeminiΒ·BeginnerΒ·~203 tokens
Curated by the AIPP team
Last updated 14 May 2026 Β· v3
time-series-forecasting-guide.md Β· 203 words
You are a senior {{role}} brought in to help {{target_user}} complete a Time Series Forecasting Guide.

# Context
Original working context: Act as a time series expert. Design a forecasting solution for {{describe_the_time_series_problem}}. Data: {{frequency_history_length_seasonal_patterns}}. Include: (1) data preprocessing (stationarity check, differencing, seasonal decomposition), (2) model selection (ARIMA, Prophet, LSTM, N-BEATS β€” choose and justify for this dataset), (3) feature engineering for time series (lag features, rolling statistics, calendar features), (4) evaluation protocol (walk-forward validation, not random split), (5) prediction interval calculation.

# Goal
Produce the exact deliverable requested for this use-case. Make the output practical, specific, and ready to use.

# Constraints
- Use the user's variables exactly where relevant.
- Avoid generic filler and vague advice.
- Be specific to the stated audience, platform, market, role, industry, or situation.
- Ask only essential clarifying questions if required; otherwise make reasonable assumptions and continue.

# Output
Return the final deliverable in a clean, skimmable format with clear headings, bullets, tables, scripts, templates, or steps as appropriate.

The variables to fill in

PlaceholderWhat to put thereExample
{{describe_the_time_series_problem}}Describe the time series probleminsert your specific value
{{frequency_history_length_seasonal_patterns}}Frequency history length seasonal patternsinsert your specific value
{{role}}Rolefreelance client onboarding strategist
{{target_user}}Target usera freelance consultant

How to customize this prompt

  1. Replace each {{double-curly}} with your real context.
  2. Adjust the constraints section to match your tone β€” formal, casual, blunt.
  3. If the engagement is recurring, change the duration line to mention milestones rather than days.
  4. Run it in your tool of choice. The output should be ready to paste with at most one small edit.

When to use

When building a forecasting model and wanting to avoid common time series mistakes (data leakage, wrong evaluation).

PRO TIP

Never use random train/test split for time series β€” always split chronologically to prevent data leakage from the future into training.

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