Why Norway rewards careful timing.
Norway is Europe's most vertical country, fjords carved by glaciers leave you staring up at 1,500-meter cliffs from sea level, and weather changes on the half-hour as you climb 800 meters in a Flåm Railway journey. The country reaches from latitude 58° N (Kristiansand, comparable to northern Scotland) to 71° N at the North Cape and 81° N in Svalbard, meaning what "summer" or "winter" looks like depends entirely on which Norway you're visiting.
The light defines the country, more than in Sweden. Oslo (60° N): June 21 brings 18 hours 50 minutes of daylight; December 21 drops to 5 hours 53 minutes. Tromsø (69° N, well above the Arctic Circle): the midnight sun runs May 18 through July 25, and the polar night runs November 27 through January 15, the sun does not rise at all. Even south of the Arctic Circle, the sky shifts dramatically, twilight stretches the whole night in June; dusk arrives by 15:00 in December.
Aurora season runs September through late March, visible only on dark, clear nights. The summer's continuous daylight makes aurora invisible regardless of solar activity. Tromsø is the most accessible aurora base in Europe (direct flights from London, Oslo, Stockholm), and Lofoten Islands deliver aurora over surreal mountain-and-sea backdrops. The peak months: December, January, February. Plan 3–5 nights in the north to maximize chances; single-night trips are a coin flip.
Bergen is the rainiest city in Europe. Average annual rainfall is 2,250 mm across 240 rainy days a year, more than triple London's. Locals don't carry umbrellas (the wind kills them); they wear waterproof shells and keep walking. Rain over the fjords is the photograph, mist halfway up cliffs, waterfalls swollen, dark green forests. Don't book a fjord trip hoping for sunshine; book one expecting rain and being delighted by clear days.
Norway is the most expensive country in Europe outside Iceland and Switzerland. Restaurant meals run €40–60 per person at sit-down dinners; mid-range Oslo hotels €180–280/night peak summer; a 1.5L bottle of supermarket wine is €18 (Vinmonopolet, the state-owned alcohol monopoly, sets prices). The single biggest cost lever is to self-cater, supermarket-bought salmon, brown cheese, and bread cuts daily food costs by €40–60 per person. The second biggest lever is to eat the dagens (daily lunch special) at €15–20, half the price of dinner.
Norway uses NOK (Norwegian krone), not the euro. Cards are universal, Norway is among the world's most cashless countries, but check that your bank's foreign-transaction fees won't eat the savings.