I due a lot of band checks at all times of the day and night.  Well, when I am awake, that is.  The other night, I checked 15 MHz to see what WWVH was doing compared to Boulder.  I can copy WWV in Boulder on 15 MHz but it isn't very loud.  The big signals for me, being so close, are 2.5 and 5 MHz.  Anyhow, WWVH was 30 over S9 using my G5RV wire on 15 megs at 9 PM at night mountain time.  I haven't heard it that strong at 9:15 PM mountain time on a wire for a super long time.  5 MHz was 30 over and 2.5 was running a solid 20 over s9 so conditions were great.  I have been listening to the Europeans on 20 meters every night at 10 PM coming in with good signals and VK ZL stations, too later in the evening on 20.  So there is lots to work on 20 during late evenings and maybe all night.  I go to bed about midnight and sleep late so I don't know what 20 is like after midnight.  When I had my 2 element yagi at 70 feet, I heard WWVH in Hawaii on 5 MHz sometimes 40 and 50 over night in the 5 to 7 A M window.  I heard W1AW many times on all bands.  I program their frequencies for each band into my QSY ER and then run the list.  I've copied W1AW on 1.8 MHZ many times, not very loud, of course, and maybe once nearly a Q5 copy but W1AW, when transmitting late into the evening, is often over S9 on 17 meters.  So, when you think the band is closed, call CQ anyway.

Phil.
K0NX