Ten Meters is back! Conditions are improving every day, since this band evolves from a dead summer band to a spectacular DX band in the peak of its season in only two months. There will be plenty of DX on this band for the next several months - until April. Within this period, some months are better than others. Spring DX on 10 is never as good as in the fall (15 is the other way around). During the winter, there are no windows over the pole into the exotic parts of Asia because of the polar night. As Maximum Usable Frequencies are trending down, the band will not stay open long past sunset. 10 is a daytime band, and during winter, propagation is almost exclusively along daylight paths.
The sun sets on the North Pole on 23 September. After October, windows over the pole will be increasingly narrow and difficult. The countries effected are mostly in southern Asia. Look for 10 meter contacts in these countries during September and October in the early morning after sunrise, and in the early evening after sunset. The rest of the world will be consistently workable until next spring.
15 Meters is also good in the fall, though the night path propagation of late spring and early summer is not part of the DX formula. Through the winter it is mostly a daytime band, with a pattern very similar to 10. During the fall, 15 doesn't get the attention it deserves because 10 is so good. Though there is less activity on 15, propagation really is excellent. Many operators will spend most of their time on 10.
For night path propagation, 20 will be the best (as always). 40 meter activity will increase as we approach winter, but 20 will be the best even then. Lowbands are best at night during the bottom of the sunspot cycle, when 20 closes on winter nights and becomes a daytime band (while 10 and 15 are dead). Southern hemisphere long path on 20 will be excellent through spring, in late afternoon and for 2 hours after sunrise.