Weather APIs Integration

Learn how to integrate popular weather APIs into your PHP applications. This guide covers OpenWeatherMap and Open-Meteo, two widely-used weather data services.

Comparison of Weather APIs

Feature	OpenWeatherMap	Open-Meteo	AEMET
Coverage	Global	Global	Spain only
API Key Required	Yes (free tier available)	No	Yes (free)
Data Points	Current, forecast, historical	Current, forecast, historical	Spanish weather data
Rate Limits	60 calls/minute (free)	Generous	Moderate
Response Format	JSON	JSON	JSON
Best For	Production apps	Development, free projects	Spanish weather

Choose the API that best fits your project requirements. Open-Meteo is excellent for development with no API key, while OpenWeatherMap offers comprehensive data for production.

OpenWeatherMap Integration

Getting Your API Key

Create Account

Visit OpenWeatherMap and sign up

Choose Plan

Select the Free tier under “Professional collections”

Get API Key

Navigate to API keys section and copy your key

Activate Key

Wait a few hours for key activation (can take 1-2 hours)

Two-Step Process: Geocoding + Weather

OpenWeatherMap typically requires two API calls:

Step 1: Geocoding API

Convert city name to coordinates:

<?php

$curl = curl_init();
$urlBase = 'http://api.openweathermap.org/geo/1.0/direct?';

include("../../claves.inc.php");

$ciudad = 'Vigo';
$url = $urlBase . 'q=' . $ciudad . '&limit=5' . "&appid=" . $keyOpenWeatherMap;

curl_setopt_array($curl, array(
  CURLOPT_URL => $url,
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => array(
    "cache-control: no-cache"
  ),
));

$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);

if (!$err) {
  $locations = json_decode($response, true);
  
  // Extract coordinates from first result
  if (!empty($locations)) {
    $lat = $locations[0]['lat'];
    $lon = $locations[0]['lon'];
    
    echo "Coordinates for $ciudad: $lat, $lon\n";
  }
}

Step 2: Current Weather API

Fetch weather data using coordinates:

<?php

$curl = curl_init();
$urlBase = 'https://api.openweathermap.org/data/2.5/weather?';

$ciudad = 'Vigo';
$lat = '42.264799151433';
$lon = '-8.765128490705925';

include("../../claves.inc.php");

$url = $urlBase . '&lat=' . $lat . "&lon=" . $lon . "&units=metric" . "&lang=es" . "&appid=" . $keyOpenWeatherMap;

curl_setopt_array($curl, array(
  CURLOPT_URL => $url,
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => array(
    "cache-control: no-cache"
  ),
));

$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  $salida = json_decode($response, true);
  print_r($salida);
}

OpenWeatherMap Response Format

Here’s a real example response from the course repository:

{
  "coord": {
    "lon": -8.7651,
    "lat": 42.2648
  },
  "weather": [
    {
      "id": 800,
      "main": "Clear",
      "description": "cielo claro",
      "icon": "01d"
    }
  ],
  "base": "stations",
  "main": {
    "temp": 18.99,
    "feels_like": 18.28,
    "temp_min": 18.51,
    "temp_max": 18.99,
    "pressure": 1019,
    "humidity": 51
  },
  "visibility": 10000,
  "wind": {
    "speed": 5.66,
    "deg": 30,
    "gust": 10.8
  },
  "clouds": {
    "all": 0
  },
  "dt": 1684000812,
  "sys": {
    "type": 2,
    "id": 2012195,
    "country": "ES",
    "sunrise": 1683954988,
    "sunset": 1684007188
  },
  "timezone": 7200,
  "id": 3126577,
  "name": "Cangas do Morrazo",
  "cod": 200
}

Processing OpenWeatherMap Data

$weather = json_decode($response, true);

// Extract key information
$temperature = $weather['main']['temp'];
$feelsLike = $weather['main']['feels_like'];
$description = $weather['weather'][0]['description'];
$humidity = $weather['main']['humidity'];
$windSpeed = $weather['wind']['speed'];
$cityName = $weather['name'];

echo "Weather in $cityName:\n";
echo "Temperature: $temperature°C (feels like $feelsLike°C)\n";
echo "Conditions: $description\n";
echo "Humidity: $humidity%\n";
echo "Wind: $windSpeed m/s\n";

URL Parameters Explained

Parameter	Description	Example
`lat`	Latitude coordinate	`42.264799`
`lon`	Longitude coordinate	`-8.765128`
`units`	Temperature units	`metric` (Celsius), `imperial` (Fahrenheit)
`lang`	Language for descriptions	`es` (Spanish), `en` (English)
`appid`	Your API key	`your_api_key`

Use units=metric for Celsius and lang=es for Spanish descriptions in your weather app.

Open-Meteo Integration

Advantages of Open-Meteo

No API key required
High rate limits
Excellent for development and testing
Simple, clean API design
Free for non-commercial use

Basic Current Weather Request

<?php

// https://open-meteo.com/

$curl = curl_init();

$urlBase = 'https://api.open-meteo.com/v1/forecast?';
$ciudad = 'Vigo';
$lat = '42.264799151433';
$lon = '-8.765128490705925';

$url = $urlBase . 'latitude=' . $lat . '&longitude=' . $lon . '&current=temperature_2m,wind_speed_10m&hourly=temperature_2m,relative_humidity_2m,wind_speed_10m';

curl_setopt_array($curl, array(
  CURLOPT_URL => $url,
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => array(
    "cache-control: no-cache"
  ),
));

$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  $salida = json_decode($response, true);
  print_r($salida);
}

echo "FIN" . PHP_EOL;

Historical Data with Open-Meteo

Retrieve past weather data:

<?php

$curl = curl_init();

$urlBase = 'https://api.open-meteo.com/v1/forecast?';
$ciudad = 'Vigo';
$lat = '42.264799151433';
$lon = '-8.765128490705925';

// Request last 10 days of data
$url = $urlBase . 'latitude=' . $lat . '&longitude=' . $lon . '&past_days=10&hourly=temperature_2m,relative_humidity_2m,wind_speed_10m';

curl_setopt_array($curl, array(
  CURLOPT_URL => $url,
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => array(
    "cache-control: no-cache"
  ),
));

$response = curl_exec($curl);
$err = curl_error($curl);
curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  $salida = json_decode($response, true);
  print_r($salida);
}

echo "FIN" . PHP_EOL;

Open-Meteo URL Parameters

Parameter	Description	Example
`latitude`	Latitude coordinate	`42.264799`
`longitude`	Longitude coordinate	`-8.765128`
`current`	Current weather variables	`temperature_2m,wind_speed_10m`
`hourly`	Hourly forecast variables	`temperature_2m,relative_humidity_2m`
`daily`	Daily forecast variables	`temperature_2m_max,precipitation_sum`
`past_days`	Include historical data	`10` (last 10 days)
`forecast_days`	Days of forecast	`7` (default)

Available Weather Variables

Current & Hourly Variables

temperature_2m - Temperature at 2 meters height
relative_humidity_2m - Relative humidity at 2 meters
wind_speed_10m - Wind speed at 10 meters height
wind_direction_10m - Wind direction
precipitation - Precipitation amount
pressure_msl - Sea level pressure
cloud_cover - Cloud cover percentage

Daily Variables

temperature_2m_max - Maximum daily temperature
temperature_2m_min - Minimum daily temperature
precipitation_sum - Total daily precipitation
sunrise - Sunrise time
sunset - Sunset time

All temperature values are in Celsius by default. Open-Meteo uses metric units.

Complete Weather App Example

<?php

function getWeatherOpenWeatherMap($lat, $lon, $apiKey) {
  $curl = curl_init();
  $urlBase = 'https://api.openweathermap.org/data/2.5/weather?';
  
  $url = $urlBase . 'lat=' . $lat . '&lon=' . $lon . '&units=metric&lang=es&appid=' . $apiKey;
  
  curl_setopt_array($curl, array(
    CURLOPT_URL => $url,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_TIMEOUT => 30,
    CURLOPT_CUSTOMREQUEST => "GET",
  ));
  
  $response = curl_exec($curl);
  $err = curl_error($curl);
  curl_close($curl);
  
  if ($err) {
    return array('error' => $err);
  }
  
  return json_decode($response, true);
}

include("claves.inc.php");
$weather = getWeatherOpenWeatherMap('42.2648', '-8.7651', $keyOpenWeatherMap);

if (isset($weather['error'])) {
  echo "Error: " . $weather['error'];
} else {
  echo "Temperature: " . $weather['main']['temp'] . "°C\n";
  echo "Conditions: " . $weather['weather'][0]['description'] . "\n";
}

Debugging Weather API Requests

Enable debugging to troubleshoot issues:

// Enable detailed debugging (development only)
curl_setopt($curl, CURLOPT_VERBOSE, true);
curl_setopt($curl, CURLOPT_CERTINFO, true);

$response = curl_exec($curl);

// Display transfer information
var_dump(curl_getinfo($curl));

Never enable verbose mode in production. It outputs sensitive information and affects performance.

Error Handling Best Practices

function safeWeatherRequest($url) {
  $curl = curl_init();
  
  curl_setopt_array($curl, array(
    CURLOPT_URL => $url,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_TIMEOUT => 30,
    CURLOPT_CUSTOMREQUEST => "GET",
  ));
  
  $response = curl_exec($curl);
  $err = curl_error($curl);
  $httpCode = curl_getinfo($curl, CURLINFO_HTTP_CODE);
  curl_close($curl);
  
  // Check for connection errors
  if ($err) {
    return array(
      'success' => false,
      'error' => 'Connection failed: ' . $err
    );
  }
  
  // Check HTTP status code
  if ($httpCode >= 400) {
    return array(
      'success' => false,
      'error' => 'HTTP error: ' . $httpCode
    );
  }
  
  // Parse JSON response
  $data = json_decode($response, true);
  
  if (json_last_error() !== JSON_ERROR_NONE) {
    return array(
      'success' => false,
      'error' => 'Invalid JSON: ' . json_last_error_msg()
    );
  }
  
  return array(
    'success' => true,
    'data' => $data
  );
}

Performance Optimization

Caching Weather Data

Weather data doesn’t change every second. Cache responses to improve performance:

function getCachedWeather($lat, $lon, $provider = 'openmeteo') {
  $cacheFile = "cache/weather_{$provider}_" . md5($lat . $lon) . ".json";
  $cacheTime = 600; // 10 minutes
  
  // Check cache
  if (file_exists($cacheFile) && (time() - filemtime($cacheFile)) < $cacheTime) {
    return json_decode(file_get_contents($cacheFile), true);
  }
  
  // Fetch fresh data
  if ($provider === 'openmeteo') {
    $weather = getWeatherOpenMeteo($lat, $lon);
  } else {
    // Use OpenWeatherMap or other provider
    $weather = getWeatherOpenWeatherMap($lat, $lon, $GLOBALS['keyOpenWeatherMap']);
  }
  
  // Save to cache
  if (!isset($weather['error'])) {
    if (!is_dir('cache')) mkdir('cache');
    file_put_contents($cacheFile, json_encode($weather));
  }
  
  return $weather;
}

Batch Requests

When fetching weather for multiple locations, implement delays:

$locations = [
  ['name' => 'Vigo', 'lat' => '42.2648', 'lon' => '-8.7651'],
  ['name' => 'Madrid', 'lat' => '40.4168', 'lon' => '-3.7038'],
  ['name' => 'Barcelona', 'lat' => '41.3851', 'lon' => '2.1734'],
];

foreach ($locations as $location) {
  $weather = getWeatherOpenMeteo($location['lat'], $location['lon']);
  
  echo $location['name'] . ": " . $weather['current']['temperature_2m'] . "°C\n";
  
  // Delay between requests to respect rate limits
  usleep(100000); // 100ms delay
}

Comparison: Which API to Choose?

Use OpenWeatherMap when:

Building production applications
Need comprehensive weather data
Require weather icons and visual assets
Want multiple language support
Need historical data archives

Use Open-Meteo when:

Developing or prototyping
Budget constraints (it’s free)
No API key management desired
European weather focus
Scientific/research projects

Use AEMET when:

Working with Spanish locations
Need official meteorological data
Require detailed Spanish forecasts
Want data from official Spanish weather stations

Additional Resources

OpenWeatherMap Docs

Official API documentation

Open-Meteo Docs

Open-Meteo API reference

AEMET Integration

Spanish weather data integration

External Services

General API integration patterns

Get Started

PHP Fundamentals

Database Programming

Session Management

Web Services

AJAX & Jaxon

API Integration

Assignments & Exams

​Weather APIs Integration

​Comparison of Weather APIs

​OpenWeatherMap Integration

​Getting Your API Key

​Two-Step Process: Geocoding + Weather

​Step 1: Geocoding API

​Step 2: Current Weather API

​OpenWeatherMap Response Format

​Processing OpenWeatherMap Data

​URL Parameters Explained

​Open-Meteo Integration

​Advantages of Open-Meteo

​Basic Current Weather Request

​Historical Data with Open-Meteo

​Open-Meteo URL Parameters

​Available Weather Variables

​Current & Hourly Variables

​Daily Variables

​Complete Weather App Example

​Debugging Weather API Requests

​Error Handling Best Practices

​Performance Optimization

​Caching Weather Data

​Batch Requests

​Comparison: Which API to Choose?

​Use OpenWeatherMap when:

​Use Open-Meteo when:

​Use AEMET when:

​Additional Resources

OpenWeatherMap Docs

Open-Meteo Docs

AEMET Integration

External Services

Weather APIs Integration

Comparison of Weather APIs

OpenWeatherMap Integration

Getting Your API Key

Two-Step Process: Geocoding + Weather

Step 1: Geocoding API

Step 2: Current Weather API

OpenWeatherMap Response Format

Processing OpenWeatherMap Data

URL Parameters Explained

Open-Meteo Integration

Advantages of Open-Meteo

Basic Current Weather Request

Historical Data with Open-Meteo

Open-Meteo URL Parameters

Available Weather Variables

Current & Hourly Variables

Daily Variables

Complete Weather App Example

Debugging Weather API Requests

Error Handling Best Practices

Performance Optimization

Caching Weather Data

Batch Requests

Comparison: Which API to Choose?

Use OpenWeatherMap when:

Use Open-Meteo when:

Use AEMET when:

Additional Resources