The 10 Meter DX season peaks in the fall during October and November, and continues through the spring. By the standards of recent years, it has been an off season. April is the month when the ionosphere starts to thin at high latitudes, closing out the DX season and returning the band to normal use (the 10-10 paper chase). Expect rapid deterioration on 10 Meters this month, and plan to spend the next several months on other bands.
The peak season for 15 Meter propagation has just begun, and will run into June. The northern hemisphere will experience later band closings in the evening, and this means the DX windows into Europe will remain open well into our afternoon. Conditions over the pole will be excellent for long haul contacts into exotic parts of Asia. These polar openings will occur during the day and into the evening. This will be the primary band for DX activity during the day, since 10 will not be much of a factor. During the sunspot peak, 15 Meter conditions were spectacular. The band was often open most of the night and day for DX, providing a rich variety of propagation paths and plenty of activity. This year's season will be off, but we can expect times when the band will remain open past midnight.
Night path propagation has returned to 20, and many nice contacts can now be made in the evening. Thursday evenings are special, because it is the Moslem sabbath. It is a good time to tune for stations in the Middle East and northern Africa. I have also had good luck with this part of the world on Wednesday evenings. Though propagation is best at sunrise peak on the other end of the path, amateurs in these countries seem to be early risers, and will work quantities of stateside stations during the hours before their sunrise. Since 20 is open all night, they have a pipeline to the states. It is important to tune carefully during the evening for these mid-eastern contacts, because the band will be loaded with Russian signals.
The Spratly operation has been postponed until this month, which should make the operation easier to work. There will be no shortage of propagation to Spratly on either 20 or 15, and the west coast will not have much of an advantage except on other bands.
All this evening propagation on 20 & 15 will take much of the emphasis off of 40, but the band will remain in great shape (with higher QRN levels). There is still considerable interest in the other low bands, but this will drop off during April.