Josh92

Hi, I am relatively new to here, and to growing Bananas, only been doing it for the last year. But I am in a similar situation where I live, summer average high is only 23 c (73 f). But I have noticed that my Musa Yunnanensis, Sikkimensis and Cheesemani in particular did quite well, all averaging about a leaf Evey 10-14 days with average temperatures in the high teens or low twenties. I got Itinerans India form and Burmese blue late in the season, Aug so can't comment much but they did both put out new leaves in September. And at the moment my Sikkimensis is growing, the cigar leaf (what has survived) from last year has started to unfurl and daytime temperature has barely gone past 8/9 c over the last few weeks.
I hope some of this helps a bit.
And do be patient, I have noticed that the bigger a plant is the faster is grows.