Something I have noticed of late is that depending on the time of day, Arena battles are easier or harder.
I live in GMT (The UK) and I tend to play my Arena battles for the incubators and relevant daily missions, in the morning between 7:30am and 10am. When I do I find my opponents far easier to win against, probably winning 3 out of every 4. As the day goes by and especially evenings in to midnight/early hours, the opponents become far harder to defeat. My assumption is that it has something to do with who is playing during other time zones.
Same for me in east coast USA. Morning battles are always easier than the ones after work.
I’d say this is even more true for the weekend tournament battles.
East Coast USA as well. Difficult between 6pm-9/10pm. gets a slight bit easier for a short time then extremely difficult from midnight on.
Different days also change where that easy late night battling is.
I used to find easier opponents late at night but lately the opponents have been super boosted or dropping. I think the word got out on my theory and I might have to adjust my battle schedule lol…