Warning: Invalid argument supplied for foreach()

Bonjour,

Je cherche a afficher différentes informations concernant la météo sur une page web.
dans le terminal de Visual Code, aucune erreures n'est détécté mais quand j'actualise ma page web, Warning: Invalid argument supplied for foreach() in C:\wamp64\www\TutoPHP\meteo.php on line 10 !!!
J'ai beau chercher, je ne trouve pas l'erreur dans mon code

meteo.php

<?php
require_once 'class/OpenWeather.php';
$weather = new OpenWeather('d06a7624b25ddfd1c5074974b8e78dc8');
$forecast = $weather->getForecast('Lyon,fr');
require 'elements/header.php';
?>

    <div class="container">
        <ul>
            <?php foreach($forecast as $day): ?>
            <li><?= $day['date']->format('d/m/Y') ?> <?= $day['description'] ?> <?= $day['temp'] ?>°C </li>
            <?php endforeach ?>
        </ul>
    </div>

<?php require 'elements/footer.php' ?>

OpenWeather.php

<?php
class OpenWeather {

    private $apiKey;

    public function __construct(string $apiKey)
    {
        $this->apiKey = $apiKey;
    }

    public function getForecast(string $city): ?array
    {
        $curl = curl_init("https://samples.openweathermap.org/data/2.5/forecast/daily?q={$city}&appid={$this->apiKey}&units=metric&lang=fr");
        curl_setopt_array($curl, [
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_CAINFO => dirname(__DIR__) . DIRECTORY_SEPARATOR . 'cert.cer',
            CURLOPT_TIMEOUT => 1
        ]);
        $data = curl_exec($curl);
        if ($data === false || curl_getinfo($curl, CURLINFO_HTTP_CODE) != 200) {
            return null;
        }
        $results = [];
        $data = json_decode($data, true);
        foreach($data['list'] as $day) {
            $results[] = [
                'temp' => $day['temp']['day'],
                'description' => $day['weather'][0]['description'],
                'date' => new DateTime('@' . $day['dt'])
            ];
        }
        return $results;
    }

}

Si quelqun a la solution :)