Summer wardrobe essentials

Hi all! First time posting in here and hope I have the right thread. I have just moved to the south of the US from the UK and have realised I do not have a suitable wardrobe for the hot sunny weather! I've convinced my hubby to take me on a shopping spree to buy more clothes but kinda don't know where to start. To give you an idea, my style is relatively casual, jeans, tshirts, Chelsea boots, leather jacket, a few nice dresses normally paired with tights etc and mostly in dark colours, navy, grey and black are my go to colours. Anyway it is a roasting hot day outside today and everything I have seems to be too heavy. Can you give me ideas on where to start building a summer wardrobe for someone who never experienced a true summer before! Thanks in advance! (Also the clothes I need are mainly for pool days, hikes, out with dog and meals etc with friends. Not office attire!)