🌦️ Weather Data Reader & Summarizer (Java)

This is a simple Java project that demonstrates how to use Streams and Records (Java 16+) to read, parse, and summarize weather data from a CSV file. The program calculates basic weather statistics such as average temperature, maximum/minimum temperatures, and the number of humid days.

---

🚀 Features

• Uses Java Records for clean, immutable data models

• Uses Java Streams for parsing and summarizing weather data

• Reads from a CSV file (data.csv)

• Calculates:

  • Average temperature
  • Maximum temperature
  • Minimum temperature
  • Number of days with humidity above 70%

• Lightweight and beginner-friendly

---

📁 Project Structure

Weather Project/
 ├── src/
 │    └── WeatherApp.java
 └── data.csv

---

📄 Sample Data (data.csv)

date,temperature,humidity
2025-01-01,12,70
2025-01-02,15,65
2025-01-03,10,80
2025-01-04,8,75
2025-01-05,14,60

---

🧾 Code Overview

The project uses a record:

record WeatherReading(String date, double temperature, double humidity) {}

And reads the CSV using Streams:

List<WeatherReading> readings = Files.lines(path)
    .skip(1)
    .map(line -> line.split(","))
    .map(parts -> new WeatherReading(
            parts[0],
            Double.parseDouble(parts[1]),
            Double.parseDouble(parts[2])
    ))
    .toList();

---

▶️ Running the Project (Command Line)

1. Compile

javac .\src\WeatherApp.java

2. Run

java -cp .\src WeatherApp

Ensure data.csv is located in the project root, not inside src.

---

💻 Setup in VS Code

Follow these steps to run the project in Visual Studio Code.

---

1. Install Java

You need JDK 17 or higher.

Download from: 👉 https://adoptium.net

Check installation:

java -version

---

2. Install VS Code Extensions

In VS Code, open Extensions (Ctrl + Shift + X) and install:

• Extension Pack for Java (by Microsoft)
• Code Runner (optional)

---

3. Open the Project

1. Go to File → Open Folder
2. Select your:

Weather Project/

VS Code will automatically detect it as a Java project.

---

4. Verify Folder Structure

Weather Project/
 ├── src/
 │    └── WeatherApp.java
 └── data.csv

❗ data.csv must be in the root folder.

---

5. Run the Program

Option A — Run Button

• Open WeatherApp.java
• Click the ▶ Run button above the main method

Option B — Terminal

Open a terminal:

Terminal → New Terminal

Compile:

javac .\src\WeatherApp.java

Run:

java -cp .\src WeatherApp

---

6. Expected Output

=== Weather Summary ===
Total days: 5
Average temperature: 11.8
Max temperature: 15.0
Min temperature: 8.0
Days with humidity > 70%: 2

---

🛠️ Requirements

• Java 17+
• VS Code or any Java-compatible IDE

---

📚 Concepts Demonstrated

• Java Records
• Java Streams
• File handling (Files.lines)
• Functional programming with lambdas
• Basic data summarization

---

🤝 Contributing

Feel free to fork this repository and submit pull requests!