Summer doldrums – a reduction of propagation on the higher HF bands during the summer months.
I take no credit for this article at all, it is the work of Thomas David Hood and was posted on Facebook by him on the 17th June, 2026 (UTC). The post was made on the Ham Radio Operators group and you can read it here, together with the comments.
I include the short piece, in his own words, as you can never find anything on this social media platform once you’ve read it. I thought this was the best short explanation of the summer doldrums that I have found. I hope that Tomas doesn’t mind me posting this and if he does I will gladly remove it.
Summer Doldrums by Thomas David Wood
I have noticed a common theme regarding propagation of the Ten-Meter band, and the perception that the solar cycle must be diving such that it becomes useless.
I wrote the propagation column in CQ Amateur Radio magazine since 2001. I’ve done much research into this topic.
Many operators on the 10 meter band notice a distinct shift in activity as summer arrives. A common misconception is that when the worldwide DX dries up in June or July, it means the solar cycle is taking a dive. The reality is that while the solar cycle certainly dictates overall band health over an 11-year period, the dramatic differences we see between seasons on 10 meters are driven by the changing angle and distance of the sun and how that naturally alters the ionosphere.
During the autumn and spring months, 10 meters comes alive for long-range global communication. The F2 layer of the ionosphere reaches an optimal density due to the sun being directly over the equator during the equinoxes. This seasonal geometry creates the perfect reflective environment for 28 MHz signals to bounce around the world.
When summer arrives, the mechanics of the ionosphere change completely. The sun is higher in the sky in our hemisphere, which causes the F2 layer to heat up, expand, and thin out. Because it is less dense, it becomes much less capable of reflecting those higher frequencies for transoceanic skip.
However, summer brings its own unique conditions with the prevalence of Sporadic E propagation. These intense, highly localized clouds of ionization form in the lower E layer of the ionosphere. Sporadic E provides incredibly strong, short-skip contacts typically ranging from a few hundred to a couple of thousand miles, temporarily replacing the global propagation we enjoy during the spring and fall.
So if 10 meters feels like a completely different band right now, do not blame the sunspot numbers. It is simply the natural seasonal shift in radio wave propagation at work. Enjoy the loud Sporadic E contacts while they last, and get ready for the worldwide skip to return when autumn arrives.