Oslo — sää kuukausittain

Although well into the northern latitudes, Oslo's climate is fairly temperate thanks to warm air being wafted across the Atlantic from the Gulf Stream. Summer weather in Oslo is mild and pleasant, with average highs around 21°C and lows of 12°C. The summer months do see frequent hot spells with daily highs around or above 26°C with warmer nights around 15°C. There are plenty of long sunny days — at midsummer the sun rises at 04:00 and sets at 23:00. There is almost two hours twilight in summer so nights are hardly dark. There is moderate precipitation (about 800 mm), December to June is the driest period. December to February temperatures are on average just below freezing, while in November and March temperatures hover just above or below freezing. Temperatures are rarely below -10°C downtown and can occasionally drop to -20 °C. Snow is most often plentiful in the forested areas and also often in the city in winter, making it a great winter sports venue.…

Oslo forum threads describe January as typically hovering around 0C but posters were clear real cold snaps down to -15C are entirely possible, with the surrounding hills making local weather genuinely variable - grey and damp near zero one stretch, then a sharp drop toward -10 to -20C the next. Snow was described as almost a given in the city through January and February, and hills just outside town like Holmenkollen and Tryvann reliably hold even more. Posters flagged one specific hazard: a mild spell can turn existing snow to ice, making the city genuinely slippery, and recommended ice grips for shoes as real gear rather than an optional extra. Daylight runs to roughly 7 hours between sunrise and sunset, and free public ice-skating in the city center was mentioned as a solid way to spend a cold day.

Regulars are specific that snow is essentially gone from the city and coast by this point, spring flowers already blooming downtown, while the surrounding mountains stay genuinely buried - a real split within a short train ride of each other. Our row backs that transitional, still-cool read, 12.2C over 2.5C nights feeling -1C, with 39mm of rain across 6.4 days and a trace of late-season snow, 9.6cm, reflecting those higher-elevation totals rather than anything falling downtown. Regulars are consistent the weather itself stays genuinely unpredictable day to day, capable of a sunny, mild afternoon or a grey, wet one with little warning either way. Layers that can be added or shed, plus a proper waterproof outer layer, remain the standard packing advice. The record: humidity 70 percent, 10 hours of sun, a 13.8 kph wind and AQI 39.

Asked whether it can snow here in May, regulars say yes - they have seen everything from freezing and snowing to close to 30C in this month - and our row keeps 3.1cm in the snow column to prove the point. The averages are milder than that sounds: 18.2C by day reading as 16C, 7.7C nights that feel like 5C, and 58.9mm of rain across 9.1 days. What May reliably delivers is 17.2 hours of daylight with 11.8 of sun. The 17th is Constitution Day, when the parade starts at ten and the city becomes a street festival - the one date in the month worth planning around. The record: humidity 67 percent, a 14.2 kph wind and AQI 43.

I don't know anything about it but I was in Oslo in June and fell in love with the city and the country so now I'm a die hard Norway fan.

July in Oslo is warm by Norwegian standards rather than by anyone else's - regulars are careful that hot here does not mean what it means further south, and note that the Oslo area peaks in the first fortnight of August, which is also when the water is warmest. Our row gives 23.8C days, 14C nights and nearly 18 hours of daylight. The question they get asked most is whether the city empties, and the answer is half-yes: most Norwegians are on holiday in July and it is quieter than May, but students stay on to keep things running and the tourists more than fill the gap. The record: 10.5 precipitation days carrying 84mm, humidity 73 percent and 12 hours of sun.

Regulars give August in Oslo as 20 to 25C by day, occasionally reaching 30C, and are careful to correct a common expectation: this city sits well outside the Arctic Circle, so there is no midnight sun - what there is, is light until about eleven in the evening. Our row reads 21.7C over 12.8C with 15.5 hours of daylight. They also say the second half of August differs little from the first and that everything is still open, while September turns cooler, wetter and noticeably darker. Rain is part of it here at 110.5mm across 11.6 days. The record: humidity 79 percent, 9.9 hours of sun, a 13.8 kph wind and AQI 35.

Oslo forum regulars call December weather usually miserable, with a genuinely wide range — “everything from grey and wet weather around zero C, or minus 10 to 20°C,” often quite wet regardless of which end of that range shows up. Snow is common but doesn't reliably stick, especially right in the city center, where fluctuating temperatures melt it fast; for a guaranteed snowy scene, regulars point to the T-bane up to Holmenkollen or Frognerseteren rather than downtown streets. Daylight runs only around 7 hours. None of it closes the city down — museums and a handful of small Christmas markets fill a 3-day itinerary regardless of the forecast. Our record: -0.9°C days, -4.7°C nights, 54cm of snow and just 1.2 hours of sun — cold, dark and genuinely snowy, more snow than the “doesn't stick downtown” framing might suggest, though a monthly total can still be light-and-melting most days with a few real accumulation events.