We had one very special day when the sun shone and the snow glistened and the views were spectacular - that day the temperatures went from -11 at lunchtime to +3 at dusk, with snow from glacier tops to beach level. It will go down as a day to remember. We drove north and west onto the Snaefellsness peninsular, right the way round its coastline, stopping to look at the Black church at Bodur, the rocky coastline, basalt columns and stayed the night in an old house which had been converted in to a small hotel at Stykkisholmur. (my room was an attic garret under the eaves, tiny but comfy).
We had one very exciting day when the winds blew and the rains came, and didn't stop all day - we drove on ice roads, with the vehicle being hit (and blown) by the storm force winds. Bizarrely the snows all melted and the temperature hovered just above freezing most of the day. Getting around was a bit of an adventure that day.
The next day we spent in Reykjavik, walking and exploring. That night, we were told the chances were okay for seeing the northern lights so out we went on a tour. All previous nights they had been cancelled because it was so unlikely. We spent 6 hours out in a jeep thing with huge Arctic tyres, being driven at FULL speed on gravel roads through snow and blizzard conditions. And no, you can't see the northern lights through cloud/snow/blizzard. We stopped for a cup of hot chocolate and a look at the rift between Europe and America. It was quite fun to see it in torch light, with huge flakes of snow. We drove back through further snow storms, and were HUGELY relieved to arrive alive back at the hotel!