June was the hottest on record. The summer ranked third hottest in history. A new all-time temperature record was set in August. And winter did not bother showing up until mid-November. The data published Wednesday by IMSEE confirms what most residents already suspected — 2025 was no ordinary year.

The Principality’s annual weather report puts an average temperature of 18.1°C on the year — 1.3°C above the long-term climate normal, and enough to make 2025 the second warmest year since meteorological observations began in 1969. Only 2022 was hotter.

A summer to remember — for the wrong reasons

Within an already exceptional summer — the third hottest on record, behind only 2022 and 2003 — June stood entirely apart. With an average temperature of 24.8°C, it was the warmest June ever recorded in Monaco, sitting 3.3°C above normal. Two prolonged heatwaves followed: the first from 28th June to 4th July, and the second — more intense — striking from 9th to 17th August, peaking at 35.7°C on 16th August. That figure broke Monaco’s all-time temperature record, surpassing even the extreme set the previous summer.

Winter that never really came

Temperatures ran above normal for much of the year, with minimum temperature records broken in both January and February. Autumn stayed mild, and the first genuinely winter-like conditions did not arrive until mid-November. December closed the year as it had largely begun — quietly, warmly, with little sign of the season it was supposed to be.

The longer trend is equally telling. Since the early 1970s, each decade in Monaco has recorded a higher average temperature than the one before. The 2021-2025 period continued that pattern, and 2025’s figures suggest nothing is changing.

Less sun, more rain days — but less rain

One of the more counterintuitive findings is the relationship between sunshine and rainfall. Despite the heat, 2025 was a notably less sunny year, recording just 1,953 hours of sunshine against a recent average of around 2,500. The reduction was sharpest in July and August, where direct sunlight fell more than 60% below what is normally recorded in those months.

At the same time, the Principality logged 67 rainy days — four more than normal — yet total rainfall of 644mm represented a deficit of 23% below the reference normal. It rained more often, but with less force. Heavy rainfall was concentrated in January and March before a deficit took hold, with a particularly dry autumn — especially October — pulling down the annual total.

Wind gusts exceeded 60 km/h on 34 days throughout the year, with the strongest gust of 95.8 km/h recorded on 21st March at the Oceanographic Museum weather station.

The full IMSEE Weather Focus report is available at imsee.mc.

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Main photo credit: Cassandra Tanti, Monaco Life