| JUBILEE | Line of underground humour not new in summer month (7) |
| AUGUSTE | White clown seen in summer month at end of performance (7) |
| COLDISH | A number, perhaps not new, in need of more heating (7) |
| MAKEHAY | A soak's ending? What, in summer month? Do this then! (4,3) |
| AQUIFER | In geology, a type of underground store of fresh, usable groundwater (7) |
| CONCAVE | Prisoner in front of underground chamber looks depressed (7) |
| NODULES | Nitrogen does spread over tops of underground lumps - these? (7) |
| CELLARS | Vendors, say, of underground rooms (7) |
| ROOTLET | Mentioned way to allow a bit of underground development (7) |
| FLAMING | Like the "Creatures" in a landmark work of underground queer cinema |
| UNITARY | Relates to single train running between outskirts of underground railway (7) |
| RHIZOME | Part of underground support? Hertz collected one in capital |
| DUNGEON | None dug out of underground prison (7) |
| ANTFARM | Provider of underground entertainment? |
| AUGRATIN | Dish topping in summer month: evaluation's not good |
| PUISSANCE | Power of car, not new, in red (9) |
| LIGHTING | Source of electricity not new in providing illumination (8) |
| PATTER | Something to be copied, not new, in way of speaking (6) |
| JUNGLE | In summer month girl has cut out middle growth that's excessive (6) |
| JULIENNE | Soup in summer month? That's about right (8) |
