Forecasts think the price cap will rise by 10% in October and stay there January, possibly not dropping again until April. The new price cap is due to be announced 27th august.
I haven't seen much talk of the cap likely going up outside of websites focused on that sort of thing, so some people may not be expecting it.
I've fixed for 12 months, it's a tiny bit more expensive than the current flexible rate but will no doubt be cheaper than the winter price cap. I wasn't sure what to do but I prefer peace of mind.