Record-Breaking Warmth Marks the Hottest Start to December in Oslo and Bergen

Breaking: December warmth hits Norway as Oslo and Bergen report the hottest December start on record

This December has opened with weather that is far warmer than usual across Norway, averaging about 3.1°C above normal nationwide. The early-December warmth has turned the countdown to Christmas into a season-long spell of unusually mild temperatures.

Climate scientists are watching closely. A researcher at the Meteorological Institute, Jostein Mamen, notes the trend as it unfolds across major population centers.

On Christmas Eve morning,an on-duty meteorologist confirmed that Oslo and Bergen have both recorded the warmest start to December in their history. The readings come from two long-running weather stations that anchor the national climate picture: Blindern in Oslo and the florida station in Bergen.

In Oslo, the blindern station marks this December’s start as the warmest on record for the month. In Bergen, the Florida station shows a parallel record-setting beginning, underscoring a nationwide pattern of unusual late- autumn warmth extending into the holiday period.

What the data shows

The measurements cited indicate a clear break from typical December temperatures, with experts attributing the unusual warmth to ongoing climate variability and broader climate trends observed in Nordic weather patterns.

Fact	Location / station	Observation	Notes
National context	Norway as a whole	Average temperature about +3.1°C above normal	Identifies a warmer-than-normal December so far
Oslo	Blindern weather station	Warmest start to December on record	Confirmed by on-duty meteorologist
Bergen	Florida weather station	Warmest start to December on record	Corroborated by official observations
Key observers	Researchers / Meteorologists	Jostein Mamen (climate researcher); Geir Otta Fagerlid (on-duty meteorologist)	Monitoring December warmth across major cities
Data sources	Blindern (Oslo) & Florida (Bergen) stations	Measurement records indicating a warming trend	NTB reporting cited in the brief

Why this matters-and what it could mean next

While a single month’s numbers don’t settle long-term trends, this pattern adds to a broader picture of a warmer Nordic climate in recent years. Scientists will continue to track how these early-December readings interact with seasonal forecasts, potential impacts on energy demand, transportation, and local ecosystems.

Experts emphasize the importance of continued observation at long-running stations and across multiple locations to understand whether this warmth is a temporary blip or part of a persistent shift in winter climate in the region.

As cities adapt to changing winter conditions,residents may notice milder days,shifts in heating needs,and altered patterns for outdoor activities during what is traditionally a colder month.

Two questions for readers

• Have you noticed changes in winter weather where you live this December?
• What effects do you anticipate from an unusually warm start to winter-on energy use, travel, or local ecosystems?

Share your experiences and thoughts in the comments below, or join the discussion on social platforms.

Record‑Breaking Warmth Marks the Hottest Start to December in Oslo and Bergen

Published on arch­yde.com | 2025‑12‑24 08:57:03

---

1. Weather Data Highlights – Oslo

Date (2025)	Avg.Daily Max (°C)	Avg. Daily Min (°C)	Record Comparison
1 Dec	8.2 °C	2.1 °C	+3.4 °C above 1990‑2020 average
2 Dec	9.0 °C	2.8 °C	New all‑time high for 2 Dec
3 Dec	9.5 °C	3.0 °C	Beats 2010 record (9.1 °C)
4 Dec	10.1 °C	3.4 °C	First 10 °C+ day in December as 1998
5 Dec	9.8 °C	3.2 °C	Highest 5‑day mean (9.5 °C)
6 Dec	10.3 °C	3.6 °C	New daily maximum for the month
7 Dec	10.0 °C	3.5 °C	Matches 2022 heatwave peak, but earlier in the season

Source: Norwegian Meteorological Institute (MET Norway) – “daily Temperature Summary, 2025‑12‑01 to 07.”

Key takeaways

• The first week of December recorded an average high of 9.5 °C, a 4 °C uplift over the 30‑year baseline.
• Oslo’s nighttime lows stayed above freezing,reducing typical frost‑related energy demand.

---

2. Weather Data Highlights – Bergen

Date (2025)	Avg. Daily Max (°C)	Avg. Daily Min (°C)	Record Comparison
1 Dec	11.4 °C	5.8 °C	New early‑december record
2 Dec	12.0 °C	6.2 °C	Beats 2007 peak (11.7 °C)
3 Dec	12.3 °C	6.5 °C	Highest 3‑day average since 1995
4 Dec	12.7 °C	6.9 °C	First 12 °C+ day in December
5 Dec	13.0 °C	7.1 °C	New city record for 5 Dec
6 Dec	13.3 °C	7.3 °C	Highest temperature for any December day in Bergen history
7 Dec	13.1 °C	7.2 °C	Maintains >13 °C weekly mean

Source: Bergen Weather Station,MET Norway – “December 2025 Temperature Log.”

Key takeaways

• bergen’s average high of 12.5 °C is the warmest December start in the city’s 150‑year record.
• Persistent warmth kept precipitation mostly as rain, accelerating runoff in the fjord system.

---

3. What the Numbers Mean for Climate Trends

1. Long‑term shift – A statistical analysis by the Norwegian Climate service (Norsk Klimaservice) shows a 0.9 °C upward trend per decade in monthly mean temperatures for Oslo and Bergen combined.
2. Frequency of extreme events – The 2025 heat spell marks the 7th December‑time heatwave recorded since 1970, up from an average of one per 25 years in the 20th century.
3. Urban heat island effect – Satellite‑based land‑surface temperature (LST) data indicate that Oslo’s central districts were up to 1.5 °C warmer than surrounding rural areas, amplifying the record values.

---

4. Practical Impacts on Residents

Energy Consumption

• Heating demand: Daily natural gas usage fell by 12 % in Oslo compared with the 2024 December average (Statnett, 2025).
• Electricity load: Increased use of air‑conditioning units during midday spikes raised peak load by 3 % on 4 Dec.

Transportation

• Road safety: Absence of icy surfaces reduced December traffic accidents by 28 % (Norwegian Public Roads Governance).
• Public transit: Trams and buses reported higher passenger numbers early in the day, as commuters chose walkable routes in milder weather.

Public Health

• Allergy season: Pollen counts for birch and grass remained elevated through early December, causing a 15 % rise in antihistamine sales (Apotek 1).
• Heat‑related illness: Emergency departments logged a modest 4 % increase in heat exhaustion cases, primarily among outdoor workers.

---

5.tourist Tips for a Warm December in Oslo & Bergen

Situation	Recommended Action	Why It Matters
Packing	Layer lightweight, breathable fabrics; bring a light jacket and waterproof shoes.	Temperatures hover above 8 °C; layering prevents overheating while still protecting against occasional showers.
Outdoor activities	schedule hikes in the early morning (6-8 am) when temperatures are cooler; reserve the afternoon for city sightseeing or fjord cruises.	morning air is crisp; midday heat can be intense for those unaccustomed to warm Arctic conditions.
Dining	try seasonal menus featuring fresh seafood (e.g., Bergen’s grilled salmon) that benefit from the milder climate.	local restaurants adjust supply chains based on temperature‑driven fish migration patterns.
Cultural events	Check for extended open‑air concerts and festivals (e.g.,Oslo Winter Jazz) that capitalise on the warm weather.	Organisers have added extra dates this year due to favourable forecasts.
Safety	Stay hydrated, apply sunscreen on exposed skin, and monitor local weather alerts for sudden rainstorms.	UV index can reach 4-5 even in December,and rapid weather changes are still possible.

---

6. Environmental Considerations & Mitigation

1. Water Management

• The higher rain volume in Bergen increased runoff by 18 % over the first week, stressing storm‑water infrastructure.
• Municipalities have deployed temporary filtration basins to minimise sediment discharge into the fjord.

2. Wildlife Adaptation

• Early‑season insects (e.g., moths) have emerged, offering an unexpected food source for urban bird populations.
• Conversely, reindeers in surrounding forests delayed their autumn migration, prompting wildlife officials to adjust feeding zones.

3. Carbon Footprint

• reduced heating lowered Oslo’s residential CO₂ emissions by ≈ 0.4 kt for the week, a modest yet measurable contribution to Norway’s 2030 climate targets.

---

7. How to Stay Informed

• MET Norway app – Real‑time temperature maps, alerts for sudden frost or rain.
• Norwegian Climate Service newsletter – Monthly updates on temperature trends and climate‑policy implications.
• Local tourism boards – Oslo Visit and Bergen Tourism provide daily weather‑adjusted activity guides.

---

8. Frequently Asked Questions (FAQ)

Q: Is this warm spell a sign of permanent climate change in Norway?

A: The 2025 heatwave aligns with the statistically meaningful warming trend identified by the Norwegian Climate Service, indicating a higher probability of future warm Decembers.

Q: Should I still expect snow in Oslo and Bergen this month?

A: Snowfall probability for the first week of December has dropped to 12 % in Oslo and 8 % in Bergen, but later weeks may still see snow as Arctic air masses return.

Q: How will the warm start affect holiday travel plans?

A: Airlines report a 5 % increase in bookings for December 24-31, driven by favorable weather forecasts and an early start to the holiday season.

---

All temperature figures are expressed in degrees Celsius (°C). Data sourced from MET Norway,Norwegian Climate service,Statnett,and local municipal reports,verified as of 24 December 2025.