Your First API Project: Getting Weather Data Made Simple

As part of my journey into API technical writing, I’ve been learning how to explore and document APIs in a beginner-friendly way. For this exercise, I chose the OpenWeatherMap API. It's a simple but powerful API that gives you real-time weather data for any city in the world.

This post breaks down what the API does, how I used it, and what I learned from the process.

---

About the API

The OpenWeatherMap API provides real-time weather data for any location in the world. You can get the current temperature, weather conditions, and more just by sending a simple request.

• HTTP Method: GET

• Base Endpoint:
  https://api.openweathermap.org/data/2.5/weather

• Purpose: To retrieve the current weather for a specified city.

---

Required Parameters

---

How to Get Your OpenWeather API Key

To use the OpenWeather API, you'll need a free API key. Here’s how to get one:

1. Go to 👉 https://home.openweathermap.org/users/sign_up

2. Create a free account.

3. After signing in, go to the API keys tab on your dashboard.

4. Copy the default key, that’s your API key.

5. You can generate a new one anytime by clicking “Generate.”

⚠️ Note: It may take a few minutes before your API key becomes active.

---

Sample Request

GET https://api.openweathermap.org/data/2.5/weather?q=Dublin&appid=YOUR_API_KEY

You can test this using tools like Postman

---

Sample Response

"weather":  [ 
  {  
    "id":  800,  
    "main":  "Clear",  
    "description":  
    "clear sky",  
    "icon":  "01n"   
  }  
 ],  
 "main":  {  
   "temp":  286.27,  
   "feels_like":  285.86,  
   "temp_min":  284.99,  
   "temp_max":  287.51  
  },
  ...
}

---

Explanation of Key Fields

Note: You can convert Kelvin to Celsius by subtracting 273.15 from the value.

---

What I Learned

• How to find and test an API endpoint.

• How to read and interpret JSON responses.

• How to document endpoints clearly for other users.

• The importance of using tools like Postman for testing.