We did a land vacation in Reykjavik. We went on a Northern Lights excursion, and at first it seemed like we would miss out on them. Then there were some, but not the real spectacular ones. The guide said the bad news now is you no longer get to do this free tomorrow night. And then on our bus back to Reykjavik, there were much better Nothern Light sightings.
The cruise I mentioned we have booked has an overnight in Reykjavik before disembarking from there. DW said we missed the Blue Lagoon last time in Iceland, so that is what she wants us to see that day.