Prophet
What it is: Time series forecasting library from Meta (Facebook) that makes accurate predictions with minimal manual tuning.
What It Does Best
Automatic seasonality detection. Handles daily, weekly, yearly patterns without manual specification. Captures holidays and special events automatically.
Robust to missing data. Gaps in your time series? No problem. Prophet handles missing values and outliers gracefully without preprocessing.
Business-friendly forecasting. Designed for business metrics like sales, web traffic, and user growth. Works well with data that has strong seasonal effects and human behavior patterns.
Key Features
Automatic seasonality: Daily, weekly, yearly patterns detected automatically
Holiday effects: Model impact of holidays and special events
Changepoint detection: Identifies trend changes automatically
Uncertainty intervals: Provides confidence bounds on forecasts
Custom seasonality: Add domain-specific seasonal patterns
Pricing
Free: Open source (MIT license)
Commercial: No licensing costs for any use
Cloud: Free software, works anywhere
When to Use It
✅ Forecasting business metrics with seasonality
✅ Data has strong daily/weekly/yearly patterns
✅ Need quick forecasts without expert tuning
✅ Have at least several months of historical data
✅ Want interpretable, explainable forecasts
When NOT to Use It
❌ Sub-hour or real-time predictions (ARIMA better)
❌ Very short time series (less than 2 months)
❌ Need state-of-the-art accuracy (deep learning models better)
❌ No seasonal patterns in your data
❌ Multivariate time series (Prophet is univariate)
Common Use Cases
Sales forecasting: Daily/weekly revenue predictions
Web traffic: Predict website visits and user growth
Demand planning: Inventory and resource forecasting
Marketing metrics: Campaign performance and conversions
Resource planning: Server load, capacity forecasting
Prophet vs Alternatives
vs ARIMA: Prophet easier to use, handles seasonality better
vs Deep Learning: Prophet simpler and faster, DL more accurate for complex patterns
vs sktime: Prophet specialized for business metrics, sktime more general
Unique Strengths
Minimal tuning: Works well out-of-the-box for most cases
Meta-proven: Powers forecasting at Facebook/Meta scale
Intuitive parameters: Business-friendly parameter names
Fast fitting: Stan backend for efficient computation
Bottom line: Best tool for business time series forecasting when you need good results fast without expert knowledge. Perfect for sales, traffic, and metrics with clear seasonal patterns. Not cutting-edge accuracy but unbeatable for ease of use and speed.