Sounds like daylight DX. It happens most Winters. Six or seven years ago I heard a station 800 miles away (CBK 540) at 1 p.m., coming in at around S3 on a portable radio.
The last couple years have been spotty, though. Where I live, usually the MW band DX fades out around 7-8 a.m. Sometimes after that there is nothing but static on DX channels.
On good DX seasons it will fade around 10-11 a.m. or so -- usually that's when the strong regionals disappear.