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How to Build a Weather App Using a Public API: A Step-by-Step Guide

Want to build a weather app quickly using a public API? This guide walks you through the process step by step—from fetching real-time weather data to displaying it in a clean, user-friendly interface. Whether you’re a beginner or an experienced developer, you’ll learn how to create a fully functional weather app with just HTML, CSS, JavaScript, and a free weather API.

Why Use a Public Weather API?

Public weather APIs provide instant access to accurate, up-to-date weather data without the hassle of manual collection. Here’s why they’re ideal for your project:

Real-time updates – Get current temperature, humidity, wind speed, and more.
Detailed forecasts – Access hourly, daily, and weekly predictions.
Geolocation support – Automatically detect user location for personalized results.
Easy integration – Most APIs use RESTful endpoints, making setup straightforward.

Popular free weather APIs include OpenWeatherMap, WeatherAPI, and AccuWeather.

What You Need Before Starting

Before coding, ensure you have:

Basic HTML, CSS, and JavaScript knowledge – Essential for structuring and scripting your app.
A code editor – VS Code, Sublime Text, or Atom work well.
An API key – Sign up for a free account with your chosen weather API provider.
A local development server (optional) – Tools like Live Server (VS Code) streamline testing.

Step 1: Set Up Your Project Files

Organize your project with these files:

index.html – Main HTML file.
style.css – Handles styling.
script.js – Manages API calls and logic.

Step 2: Fetch Weather Data from the API

Use JavaScript’s fetch() to retrieve weather data. Here’s an example using OpenWeatherMap:

const apiKey = "YOUR_API_KEY";  
const city = "New York";  
const url = `https://api.openweathermap.org/data/2.5/weather?q=${city}&appid=${apiKey}&units=metric`;  
 
fetch(url)  
  .then(response => response.json())  
  .then(data => displayWeather(data))  
  .catch(error => console.error("Error fetching data:", error));

Pro Tip: Always check the API documentation for required parameters and response formats.

Step 3: Display Weather Data on the Page

Create a function to render weather data in your HTML:

function displayWeather(data) {  
  const weatherDiv = document.getElementById("weather");  
  weatherDiv.innerHTML = `  
    <h2>${data.name}, ${data.sys.country}</h2>  
    <p>Temperature: ${data.main.temp}°C</p>  
    <p>Humidity: ${data.main.humidity}%</p>  
    <p>Wind: ${data.wind.speed} m/s</p>  
  `;  
}

Ensure your HTML includes a <div id="weather"></div> placeholder.

Step 4: Add Geolocation for Auto-Detection

Enhance user experience by detecting their location automatically:

if (navigator.geolocation) {  
  navigator.geolocation.getCurrentPosition(  
    position => {  
      const { latitude, longitude } = position.coords;  
      fetchWeatherByCoords(latitude, longitude);  
    },  
    error => console.error("Location access denied:", error)  
  );  
}

Step 5: Style Your App with CSS

Make your app visually appealing with clean CSS:

#weather {  
  background: white;  
  border-radius: 8px;  
  padding: 20px;  
  text-align: center;  
  width: 300px;  
}

Step 6: Deploy Your App

Share your weather app using:

Netlify (easiest for static sites)
Vercel (great for frontend projects)
GitHub Pages (free for public repos)

“The best way to learn is by building—and a weather app is the perfect project to start.”

#webdev #coding #weatherapp #API #javascript

How to build a weather app with a public api

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