Hi Bryan,
This is the scenario which is often defined as multi-class classification problem and the choice of algorithm can depend on various factors, including the size of your dataset, the complexity of the decision boundary between classes etc.
Here are a few algorithms that are commonly used for multi-class classification tasks, which you might consider:
- Decision Trees
- Support Vector Machines
- Neural Networks
- K-Nearest Neighbors
Given RGB values as predictors, which can capture complex patterns, and aiming to classify into one of 24 hours, a model that can handle high-dimensional data and complex relationships well, like a Neural Network, might be particularly suitable.