Luggage and bags:
A day (back-)pack for town walking and short day excursions around the city.
Clothing/Shoes/Weather Gear: The winter season is loooong in Tromsø, and summers might be fairly wet and cold. Do bring sturdy walking shoes for town use and boots for off-road hikes.
Toiletries and Medical Supplies: Do not forget sunscreen (you can also buy there) if boating or skiing. Mosquito repellent is highly advisable for the summer.
There is no special rainy season.
Avg. Temp. in Spring: max.: 0 – 7°C ( 32 - 45°F); min: -4 - 2°C ( 25 – 36°F )
Avg. Temp. in Summer: max.: 9 – 15°C ( 49 - 59°F ); min: 6 - 9°C ( 43 - 49°F )
Avg. Temp. in Autumn: max.: 2 – 9°C ( 36 - 49°F); min: -2 - 4°C ( 28 – 39°F )
Avg. Temp. in Winter: max.: -1 – 9°C ( 30 - 32°F); min: -5 - -4°C ( 23 - 25°F )
Remember that it can be pretty cold here also in summer. From September to May bring warm clothes. From May to August bring both warm clothes and some summer clothes for 'hot' days.
But you do not need to bring your warmest winter clothes in summer....
Toiletries and Medical Supplies: Hm.... you can buy it all!!!! :)
Photo Equipment: In Norway you get whatever you need of the equipment, but it can be more expencive than you are used to.