KD6RF (7547km) was the first USA station to spot my 10m 500mW WSPR beacon at 1454z today.
UPDATE 2004z: So far I have been spotted by 5 different USA stations on 10m WSPR and 10 different stations in 4 continents today.
UPDATE 2126z: The last USA WSPR spot of me was at 1956z by K3GEN (5883km). I suspect this will have been the last USA spot tonight, but I will continue beaconing for a while longer.
UPDATE 2204z: No further USA spots since K3GEN at 1956z. I think we can assume the USA opening on 10m has ended. Will now go QRT on 10m WSPR but will stay on 630m (472kHz) overnight.