It is mid-summer, a time of year when most DX activity is concentrated on 20 Meters. This is because the low bands are out of season, while the day paths on 10 and 15 are seriously effected by an overheated ionosphere. The only reliable DX paths span areas of darkness, and are primarily on 20. Whereas daypath propagation is out of the picture on 10 Meters for several months, the summer effect on 15 isn't as severe. We can expect improvement across day paths on 15 during August and September, though evening propagation to Europe and Asia will continue to deteriorate. By autumn 15 will be a day path band. August propagation on 15 is not the best, and the short path to Europe usually opens late. For the first couple hours of the day, long path is often open instead - to Europe and Africa. For one more month, most DX activity will remain on 20.
The fall DX season is just around the corner, and this is especially good news to contemporary novices who only work one band and mode. 10 Meters is coming back! Expect some improvement on this band around the end of August, with dramatic improvement all thru September.
For now, the most reliable and predictable band will be 20 Meters. All through the sunspot peak we have daily long path openings year-round. The low end of the CW band is home to many highly skilled and experienced DX'ers who enjoy competing with each other in pileups across a great variety of paths. There are, however, portions of this fine DX band where the competition is much less professional. The propagation is the same, but there is so much more to contend with. There are less DX stations to work in the phone bands, but more rare DX. There are aspects of SSB DX operation (especially on 20) which are distasteful to many, but not nearly as dreadful as the thought of dusting off the key and using it. It is not surprising that many SSB ops prefer 10 or 15 over 20, usually for reasons unrelated to propagation.