What should I pack for the last week of August in the UK?

What should I pack for the last week of August in the UK?
Edit: Thank you all for the helpful suggestions! It turns out that my original trip plan isn’t what we expected, so I’ve started a new post for anyone who wants to assist us in better planning our journey. You can find it here:
https://www.reddit.com/r/uktravel/comments/1j9nt9s/help_plan_our_uk_trip/
I’m an American visiting the UK for the first time for a friend’s wedding, and I’m a bit unsure about what to pack! I’ve seen various suggestions like “be prepared for all types of weather, bring everything, and layer up!” but as a diligent planner, I’m hoping for more specific advice. Additionally, if someone could recommend an outlet converter, I would greatly appreciate it! I’ve come across different types online, and I’m not sure which one to choose.
We’ll be flying into London and then heading to Cardiff, Warwick, Oxford, and lastly, we’ll attend the wedding just outside of Ipswich. Our trip is scheduled from August 25th to August 31st.
For some context, we aim to fit in as much sightseeing as possible. My partner and I fell in love with the history of castles during our visit to Switzerland (something the US just can’t compete with!), so we’re excited to explore Cardiff and Warwick castles. We also plan to go on a wine tour, visit some museums in Oxford, and hopefully squeeze in some hiking if our schedule allows between our travel and wedding events. Thanks in advance for your help! 🙂
It sounds like an exciting trip! Here’s a more detailed packing list to help you prepare for the varied weather and activities you have planned in the UK during the last week of August:
Clothing:
A light scarf (it can add warmth and style)
Bottoms:
A nice outfit for the wedding (don’t forget accessories!)
Footwear:
Waterproof shoes or hiking boots if you plan to hike
Accessories:
Toiletries & Essentials:
Electronics:
Additional Tips:
For your castle visits and outdoor activities, let’s hope for lovely weather, but do prepare for some rain just in case. Enjoy your trip and have fun at the wedding!