Short answer: No. It is different over here.
Long answer: The weather in Pokemon Go is drawn from some weather data provider. All the following is under the provisions of "I am not entirely sure" and "might not always be the case" and "might vary by region": As far as I know it is the same provider that also appears on the phones default screen. Most often this is AccuWeather. Their model has pretty low spatial resolution, as it was developed for the USA. Probably the relevant parts for your region actually did have cloudy weather in the morning.