Very late last night, 10m yet again was open across the Atlantic to the USA. N2OTO (7088km) was spotting my 2W at around 2312z at -16dB S/N and a little earlier WB2TQE (7097km) was copying me slightly less strongly. Although most probably multi-hop Es, it is just possible it was F2 back-scatter from near the equator. 10m has opened to the USA very many times this summer. I think I have caught 8-9 openings now, and I will have missed a few.
These are just the sort of fleeting openings that regular WSPR operation will reveal.