International Climate Comparison: The "Elevation-Defying" Cfa Island of Stachen (425m)

[Mazat]

Hi everyone

To provide a deeper context to my previous posts about the Stachen Microclimate, I have compiled a comprehensive global comparison. This data covers the period from 2014 to 2025 and pits my 425m (1,394 ft) enclave against some of the most famous palm-growing regions and maritime hubs in the Northern Hemisphere.

Scientific Integrity:
To ensure the highest accuracy, I have applied a conservative -0.3K safety adjustment to my annual means. This accounts for potential "heat spikes" in my solar-ventilated Bresser station during late afternoon periods when the solar fan might deactivate while the sun is still low.

List (2014–2025):

Location	Elevation	Annual Mean	Absolute Minimum
Santa Barbara (USA)	4 m	15.5 °C	-1.0 °C
Washington D.C. (USA)	5 m	15.4 °C	-14.0 °C
Bologna (IT)	37 m	15.0 °C	-8.0 °C
Venice Lido (IT)	4 m	14.7 °C	-7.0 °C
Verona (IT)	68 m	14.5 °C	-10.0 °C
Milan Malpensa (IT)	234 m	13.8 °C	-11.0 °C
Lyon (FR)	201 m	13.8 °C	-10.0 °C
Lugano (CH)	273 m	13.7 °C	-6.0 °C
Magadino (CH)	203 m	12.6 °C	-9.0 °C
STACHEN (CH)	425 m	12.5 °C*	-11.0 °C
Seattle (USA)	6 m	12.2 °C	-10.0 °C
London Heathrow (UK)	25 m	12.1 °C	-7.0 °C
Brest (FR)	99 m	12.1 °C	-7.0 °C
Kehelland (Cornwall)	87 m	11.6 °C	-5.1 °C
Constance (GER)	428 m	11.0 °C	-11.1 °C

*Adjusted by -0.3K safety margin.

Key Observations:

1. Elevation Efficiency: Despite being located 400m+ higher than London, Seattle, or Brest, Stachen outperforms them in annual mean temperature. This highlights the power of our local "Heat-Engine" and the Cfa (Humid Subtropical) characteristics.

2. The "Milan Pattern": Our absolute minimum of -11.0 °C is identical to Milan-Malpensa. We share the same winter resilience and summer heat-sum as the northern Po Valley, but at nearly double the elevation.

3. Regional Anomaly: The 1.5°C gap between Stachen and the regional reference in Constance (same elevation) confirms that our "Solar-Trap" setup and hedge-protection are creating a unique climatic island.

Whether you are growing Trachycarpus, Jubaea, or even testing Strelitzia (which successfully overwintered here!), these numbers show that microclimate is often more decisive than latitude.

Best regards

Mazat

 

 

[Foxpalms]

@Mazat This is the St James's park data London. There are slightly warmer areas/microclimates, for example here but this is London's mildest official station. 12.7c average.

[Mazat]

On 5/5/2026 at 2:43 AM, Foxpalms said:

@Mazat This is the St James's park data London. There are slightly warmer areas/microclimates, for example here but this is London's mildest official station. 12.7c average.

Thank you so much for the data and your insights, Foxpalms—that’s really fascinating. A friend of mine from Ireland, near Dublin, once told me that there are some very mild areas in London. It’s truly fascinating to see how different locations and conditions create heat islands. Our guests here are usually in for a shock because of the temperature differences when they visit from places as far away as 15 minutes, but they like it. Otto, who travels all over the world on business, is amazed every time; he was in Manaus just last year and near Miami the year before last—he almost stayed there, he liked it so much. He hasn’t been to London yet, only near Liverpool, but it’s nice and cooler there, isn’t it?

[Foxpalms]

On 5/7/2026 at 9:39 PM, Mazat said:

Thank you so much for the data and your insights, Foxpalms—that’s really fascinating. A friend of mine from Ireland, near Dublin, once told me that there are some very mild areas in London. It’s truly fascinating to see how different locations and conditions create heat islands. Our guests here are usually in for a shock because of the temperature differences when they visit from places as far away as 15 minutes, but they like it. Otto, who travels all over the world on business, is amazed every time; he was in Manaus just last year and near Miami the year before last—he almost stayed there, he liked it so much. He hasn’t been to London yet, only near Liverpool, but it’s nice and cooler there, isn’t it?

Yes Liverpool is quite a bit cooler than London. Though it is still mild enough for canary island date palms to grow there. They tend to get more Atlantic westerlies whist during the winter Atlantic westerlies are more common in London it’s more from the south west direction. Even February sun here can heat those tropical/subtropical air masses up from the canaries sometimes into the high teens.  Whilst spring and summer we get much more continental heat and southerly winds coming up from France/Spain and occasionally Africa. 

Besides having one of the largest heat islands in the world London also has hills to the south, as well as the north. Then some lower elevation ones to the west whilst the east has none. Which also helps the trap the heat in. As well as block the wind. For example London city airport can sometimes be 2-3c cooler on hot days compared to central and western London. As there is a cool breeze flowing down the Thames estuary originating from the North Sea. Here’s it’s possible to grow 9b plants and even some 10a plants in microclimates. Ensete Ventricosum and monstera year after year I see be left out as summer bedding plants and they continue growing in spring with only partial damage. I have not been to Lake Constance but on wunderground map it clearly shows the microclimate differences when I last looked. It’s always amazing how a short distance can have such a sudden change on the temperature and weather in some areas. Which is why the canaries and Hawaii's climate always fascinates me.