It's challenging to pinpoint the exact temperature at any given time, so here's a breakdown for reference:
May: Ranges between 5°C to 8°C due to the melting season.
June: Still melting, varying from 7°C to 12°C.
July: Typically between 11°C to 19°C, influenced by remaining snow in high mountains and the Hardangervidda plateau. If little snow remains with hot air temperatures, water can be warmer by mid-July. Some summers, guests opt-out of wearing wetsuits by then.
August: Ranging from 10°C to 17°C.
September: Varies from 9°C to 15°C.
October: Usually between 8°C to 13°C.
Outdoor Norway provides guests with essential gear like a wetsuit (John), wetsuit jacket, neoprene river boots, and a water-resistant/wind-resistant jacket to ensure warmth.
Additionally, if you ask a Vestlander (a Norwegian from the west), they might simply say, "The water is fresh." This implies it's never too cold, always suitable for adventure—all you need is the right equipment.