When travelling, it's generally smart to pack in preparation for rain or any other conditions that may arise. The rainfall in Grande Prairie is roughly similar to Copenhagen. You can assume this to be the case over the next 17 days.
Expect the weather to be around 23 °C on average in July. As the temperature peaks, try to get your plans done early, as flight price and availability will have an impact on your travels. The climate in Copenhagen is generally colder than in Grande Prairie.