How can this happen ? (climate, snow, warm, recorded)

[dhdh]

Today was a fairly normal January day in Nice. Morning was sunny with a temp of around 7°C and afternoon partly cloudy with a temp of 13°C. Around one degree warmer than average but nothing too special.

After hitting a high of around 13.5°C at around 4pm, the temperature started to decrease at 5pm at sunset to around 13°C. Completely normal.

However, completely unlike what would be expected, temperature started to rise abruptly at 6pm, hitting more than 18°C at 8.30pm in pitch darkness under clear skies (19°C where I live) and remaining at around 17°C for the rest of the night. I was going out for dinner with friends tonight and as I stepped out from home at 8pm I instantly felt it was abnormally warm.

I know Nice has a mild Mediterranean climate but 18°C at night in January sounds more like Miami than a European city, at 43°N, in its coldest month. It is very unusual and I believe we broke a record for January 5. (Edit : both Miami and Hong Kong had a colder night...Hong Kong was even 8°C colder at the same time of the day despite being at 22°N )

My question is, what causes such a warm night to happen, at that latitude, in this season, at that time of the day, and especially after a very typical cool 13°C day ?! Humidity is very low (25%) if that can help.

I loved it though, I wish every winter day was like that here !

Edit : Right now at 2.15 am, it's 14°C

[Joe90]

Foehn wind? There was an October evening here a few years ago, when the temp rose to 24C/75F at 4.00 am, after a low of 9C/48F earlier that night (monthly average min 7C/46F). It was caused by a destructive foehn wind that leveled a few thousand acres of pine plantation. It was a most unusual experience. Our place had a gentle warm breeze rather than the strong wind.

The local weather maps should be able to paint a clear picture of what the cause in Nice was.

[wavehunter007]

That type of thermal antics are not all that strange in the lower portions of temperate latitudes.

In the lower portion of the middle latitudes of the northern hemisphere (30 to 45 North), changes in wind direction, frontal passages, and even advancing precipitation, can make a huge impact of surface air temps in a short time…esp in the winter season. At this time of year, diurnal sun control can often be subordinate, as moving low and high pressure areas, fronts, dip/rises in the jet stream…etc can all bring a quick change in temp to the lower middle latitudes. This can happen at night as well as durning the day.

Here in on the East Coast of the USA, I can remember many winter days that were modestly chilly, with highs struggling to get above 7 C with full sun …then as night fell, and a strong low tracked to the west, southerly winds would bring warm subtropical air …and by midnight the temp might rise to 17 C. It’s not uncommon for weather stations in many parts of the world to report the daily high after dark several times a year before a frontal passage.

[tom77falcons]

Originally Posted by dhdh

Today was a fairly normal January day in Nice. Morning was sunny with a temp of around 7°C and afternoon partly cloudy with a temp of 13°C. Around one degree warmer than average but nothing too special.

After hitting a high of around 13.5°C at around 4pm, the temperature started to decrease at 5pm at sunset to around 13°C. Completely normal.

However, completely unlike what would be expected, temperature started to rise abruptly at 6pm, hitting more than 18°C at 8.30pm in pitch darkness under clear skies (19°C where I live) and remaining at around 17°C for the rest of the night. I was going out for dinner with friends tonight and as I stepped out from home at 8pm I instantly felt it was abnormally warm.

I know Nice has a mild Mediterranean climate but 18°C at night in January sounds more like Miami than a European city, at 43°N, in its coldest month. It is very unusual and I believe we broke a record for January 5. (Edit : both Miami and Hong Kong had a colder night...Hong Kong was even 8°C colder at the same time of the day despite being at 22°N )

My question is, what causes such a warm night to happen, at that latitude, in this season, at that time of the day, and especially after a very typical cool 13°C day ?! Humidity is very low (25%) if that can help.

I loved it though, I wish every winter day was like that here !

Edit : Right now at 2.15 am, it's 14°C

Strong warm front I would think crossing your area at that time. Maybe bringing in warm air from the tropical Atlantic. Trust me, I'd be ecstatic with your normal temps.

It seems like Nice France probably experienced a sudden wind direction change during that time. If the wind was from the West up to around 5pm, then the wind direction probably changed abruptly to the South or Southwest around 6pm, and bringing in a much more warmer air mass.

For that same time period, it seems like Hong Kong and Miami had steady North winds bringing in cooler temperatures over there.

Other than Nice France, Rapid City South Dakota was warmer than Miami earlier today but during the day time instead.


For most months of the year, it seems like consistent North winds and East winds bring colder than average temperatures for Nice most of the time, West winds average temperatures, and South winds above average temperatures.

[dunno what to put here]

This happens a lot here. We're located on the lee side of the mountains.

I recall somewhere in the UK recording its maximum temperature at midnight after it rose to 22C/72F

There was also a night in December, when the temperature fell to -3C / 27F, a slight wind increased and the temperature soon rose to around 2C / 36F

[ben86]

^^ It certainly does happen a lot in this country - the latest ever 20C recorded in this country happened on 18 November 1997 in a village called Aber on the leeward side of the Welsh mountains (a place which holds a lot of winter national high-temperature date records because of the microclimate), where it was 20.7C at 7pm, about three hours after sunset. Ironically even in midsummer there's no date when Aber averages as high as that...

Even here the passage of fronts and change of wind direction often has a bigger impact on midwinter temperatures than the weak sun. So far this winter 40% of daily highs have happened after dark (today is one of them), which gets less normal the further from the solstice we get.

[CairoCanadian]

Back when I lived by the sea in Victoria, BC, relatively little of our daily variation came from the sun.

I remember during a miserable arctic outflow day with temperatures around 1C a powerful west wind lifted it right up to 12C in the middle of the night. I was so happy seeing all that snow melt!

[dunno what to put here]

Temperature is 9.6c here at 0:16am, and has risen since the evening.

[Proterra]

18°C in Nice doesn't sound too weird... We've seen temperatures up to 15°C in Kraków this week, without Halny...

Now, that is weird...