I live on top of mountain above Old Fort. It is 44 degrees at my house for a low this morning, and I drive down to town and it's 28 degrees. I think my whole property is a microclimate. Now when it snows this week, I'll be 5 to 10 degrees colder than surrounding lowlands, but it doesn't snow often here. Wierd weather here!

That's not uncommon for elevated areas that aren't high enough for the altitude to bring the low temperatures down - cold air sinks, so the surrounding valleys are cooler on the typical night. Conversely, one potential drawback (for those producing citrus) is that the air cools down more quickly in the evening due to the fact that there is less mass around, so while the low might not be as severe, the low is often longer in duration. Also, when there is an advective cooling event, the overall lower thermal mass of the hill/mountaintop environment means that the temperatures may be cooler - as you've observed during the snowstorms.

Microclimates are interesting.......especially this time of year when some areas have damaged plants from freezes while other areas have not seen a freeze. I was in Boston this past weekend and they did not have a killer freeze yet while my yard has seen 22F (-5.5C).......and I'm 30 miles south of Boston.

I almost never get my first freeze until November 12 every year for reasons stated above and my musa basjoo banana is still green despite having a touch of 30 degrees one morning about two weeks ago. But, tonight as usual, winter is back on schedule with high winds, snow, and low 20's predicted, so I've battened down the hatches on the young citrus!

I find the discussion on micro climates and weather very interesting... and to put this into a citrus perspective can mean success or failure of a citrus tree - especially for those of us out of the citrus growing areas.

During October, here in the Metro Vancouver area we were under a strong ridge of high pressure for much of the month. The result was a temperature inversion. Sea level was experiencing mostly cloudy days and temperatures up to about 12C or about 54F. While it was clear and sunny on top of the 1200m or 4000' mountains. The temperature were above the 20 degree C mark (72F) on the top of the mountains.

Now, I certainly don't live in a citrus area, but i have found a spot in my garden where there is as close to an ideal spot to grow my citrus as I will get. It is east facing with unobstructed sunshine (when its out ). My neighbours and my front lawn will loose whatever snow we get before anywhere else on my street. a very slight elevation gain of perhaps 2 meters (9'). Thats all its seams all it take. Add the heat loss from my house into the ground, and warmth of the winter sun reflecting off the house all contribute to a very localized micro climate.

My Meyer 3m (9') lemons thrive in this spot - they have been in bloom since the end of April and are still in bloom as we speak. I also have a Changsha, Sudachi, Nippon Orangequat, Juanita Tangerine, Bearrs lime and a Boquet de Flours orange. All lined up in a row in this micro climate - this winter will be the first test for the lime and sour orange.... In the next week or so I will be covering them up for the approaching winter. The snow is falling on the local mountains no so i know that winter is coming.

Greg

This is a very interesting topic.
We all are hardy citrus enthusiasts and naturally are stretching up our achievements.
Sometimes it becomes misleading and invites others to test the particular varieties in what they think resembles their climate.
I believe that many plants are being destroyed because of this "mis"information.
It would be decent to communicate the exact temperatures and their duration at the spot, not just the conditions at nearby airport.
One of the examples is the citrandarin growing close to Trachycarpus fortunei at Sterling garden of Panamajohn. My brother lives few miles from this place and I am visiting him very often, no way trachies can survive there without zone stretching due to the very particular conditions.
It would be very instructive to know how the particular microclimates are achieved.

Why do you need a micro climate with weather like this?

http://www.weather.com/weather/tenday/North+Charleston+SC+29418

Tonight we are forecast to get down to some good old fashioned Colorado temperatures. Tonight lows are forecast to be between -10 F to -14 F (-23 C to -25 C). Many of the ski areas received 6 to 22 inches of new snow. - Millet

This is one of the worst winters since I planted outside... Today Hi / low 28 & 16 (-2 / 9c) Saturday 25 / 14 ( -4 / -10c ) Sunday 25 / 16 ( -4 / -9 )........

YIKEs!!! keeping my fingers crossed and my 7 watt christmas lights on

Hi Greg,

Have put my november temperatures on this board under 'citrus in england'. So far 4hrs or so of frost with lowest temp so far -2.6*c.

No frost so far in december, today is cold at 6*c with a low tonight of 3*c and then warming up over weekend.

My potted cold tolerant citrus collection are under fleece which is supposed to protect to -7*c.

Climate here is supposed to be similar to yours but no one has c9 christmas lights here anymore, all shops sell leds.

Hope to put my plants in ground in spring if they survive. Good luck with yours.

I went out of town for the weekend and so I brought my potted citrus collection indoors just in case. The in-ground Meyer's seems ok.