From -30 °C to + 30 °C within one day

From -30 °C to + 30 °C within one day

Thu, 07/06/2018 - 16:25
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by Caroline Coch

Everybody knows that while there is winter in the northern hemisphere, it remains warm near sea level in the tropics. I have always been aware of this – but experiencing this climate difference within one day was truly fascinating.

I am a doctoral researcher in Germany doing Polar Science. My research looks at small rivers that flow across permafrost – permanently frozen ground. For my project, I get to travel to remote places in the Canadian Arctic and to attend conferences all over the world. Polar scientists like to meet in the cold. In December 2017 I attended the Arctic Change Conference in Quebec City in the eastern part of Canada. Packing for this trip was rather challenging because I knew that I would be spending Christmas in the Caribbean just after the conference.  

 The climate in Québec City is cold and temperate. The average temperature over the year is 4.8 °C. Québec City receives 1101 mm of rainfall during one year on average. In comparison, London has a yearly average of 11.1 °C and a total yearly rainfall of 621 mm. While the mean December temperature in London is 5.6 °C, Québec City experiences mean December temperatures of -8.1 °C. Typical for a continental climate, the temperatures vary strongly between the months (by 31.0 °C).
Climate Chart of Québec City (Canada). The red line shows the monthly average temperature, and the blue bars the monthly average precipitation from January (01) to December (12). Source:


The week of the conference was extremely cold, with a minimum air temperature of -20.6 °C. The wind chill (which is the temperature we feel on our body taking the wind into account) was -30 °C most of the week. Many Canadian cities have an extensive tunnel network so that people can move around the city without being exposed to the extreme cold. The conference center was connected to the hotel making it very convenient to access while the storm went on outside. Finally, the wind calmed down and made the exploring of the city centre very enjoyable.

While repacking for my trip to the Caribbean it felt very odd moving my woollen sweater and mitts from my small backpack far down into my large luggage. It turned out that all my summer clothes took about the same volume as a few winter pieces. I could not imagine myself wearing a summer dress as it just had started snowing outside again. Anticipating that my Christmas feeling would vanish quickly, I made my way to the airport and waved goodbye to the beautiful Canadian winter. This was going to be my first Tropical Christmas.

As we approached Puerto Rico’s San Juan I could already spot a few palm trees. Suddenly, I got very excited about this wall of heat welcoming me. While people started picking up their luggage, it dawned on me that my huge bag full of winter clothes must still be in Philadelphia, where I had to rush to catch my connecting flight. I actually felt a little bit relieved that I did not have to carry all my unnecessary winter clothes.  

 With only my summer clothes in my small backpack, I stepped outside the airport and I was welcomed by the tropical air. It truly felt amazing. It was already night-time and I could just be short-sleeved outside. Already at first sight, San Juan’s climate chart looks very different to the one from Québec City. The climate in Puerto Rico is tropical and dominated by rainfall all year round, which is on average 1683 mm per year. The mean annual temperature is 25.6 °C, and varies only by 3.3°C between the months. The December average is 24.6 °C.
Climate Chart of San Juan (Puerto Rico). The red line shows the monthly average temperature, and the blue bars the monthly average precipitation from January (01) to December (12). Source:


Puerto Rico experiences the Atlantic hurricane season – it was most recently hit by hurricanes Irma and Maria. Nonetheless, this tropical country is a great Caribbean travel destination. Although the Island is very small in size – roughly half the size of Wales – there is so much to explore. If I had known that the “Beast from the East” was awaiting me in the UK after my return, I would have just stayed on this beautiful Island. It is truly remarkable that our globalized world allows us to experience such temperature extremes within one day.

Beautiful colonial-style houses in Old San Juan.
Beautiful colonial-style houses in Old San Juan. 
Steps beach at Rincón on the western side of Puerto Rico is ideal for snorkelling in calm conditions and for surfing in windy conditions. 
Cacti at the more arid south side of Puerto Rico, near Guánica.
Cacti at the more arid south side of Puerto Rico, near Guánica.