Days of extreme heat are not uncommon during the summer months in the Philadelphia, PA area. Even if the weather authorities have not issued a Heat Advisory or an Excessive Heat Warning, heat-related illnesses or conditions can occur in warm weather. The experienced staff at AFC Urgent Care can assist. What are some summer-related illnesses or conditions? High temperatures and humidity often cause heat illnesses and heat-related conditions. Summer illnesses include: Heat rash - A minor ...