Any traveller to Reykjavik should be aware that in some ways, there are two Reykjaviks for tourists: the summer Reykjavik, and the winter Reykjavik.
Reykjavik in the summer loves tourists. The Gulf Stream keeps it relatively warm, though cloudy most days; there are lots of hotels, camp sites, museums, and a wonderful bus system that runs every day, 07:00 to 24:00.
From the end of August until December, the city’s tourist sites gradually close up; the museums offer reduced hours, and the bus schedules get restricted. All the same, there are some great parts of Reykjavik that can only be experienced in the winter. The Christmas season is a city wide celebration, and the aurora borealis is probably the most amazing light show in the world. And again, thanks to the Gulf Stream, Reykjavik isn’t as cold as many travellers might expect - average winter temperatures are around -1 C. If you do go to Reykjavik in the winter, be prepared for darkness. While Reykjavik doesn’t ever lose sunlight entirely, two hours of twilight a day doesn’t feel like daytime to those of us from further south!