The below temperature map is certainly depressing. Here in Tucson, more of the same for tonight. Actual low temp here at my weather station is now 14.6, the low as 14.4 with winds 13 gusting 21. I guess I can plan on replacing my citrus. This temp represents an historic, all-time low.

Believe it or not, the below picture is from downtown Tucson:



I'm sure there will be a run on replacement citrus in a month or so. These temps are the lowest since 1889!!!!!

Pertman, what kind of citrus do you have? Those temperatures are very cold for Arizona.

I had (whether they are still alive is another question):

Varigated Pink Eureka Lemon
Mexican Lime
Washington Navel
Moro Blood Orange
Rio Red Grapefruit
Valencia

They were protected with frost cloth, xmas lights and 250 watt halogen worklights.

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I guess historic (since 1889) lows will defeat my protections. It is supposed to be at least as cold, if not colder tonight. Generally, the low temps here are in the high 20s, but in a La Nina year, anything is possible. One forecast has this cold sinking all the way to Cancun Mexico.

Regards,

Peter

New Mexico looks extremely cold! Is cold this severe normal for New Mexico? This is not a normal La Nina winter for sure. I think a low of around 40F was reported in Cuba back in December! I am expecting a massive fish kill here in local waters. The water temperatures around here are in the low to mid 40s and this is danger zone for spotted trout especially. This is about 20 F below average! I think it will be at least a month before the water temperatures are warm enough for swimming.

By the way does anyone have a preference for monitoring temps? I've been using weatherunderground and Accuweather.

There is more cold coming next week especially for the southeast! I hate to bring such bad news but that is the forecast! This freeze will end tomorrow night and then another on the way Tuesday! This is a La Nina year and a strong one and yet the arctic air keeps coming south. It looks like the scond half of February will be mild and hopefully stay that way.


I wonder if this is the beginning of an ice age? This may sound extreme with all the global warming hype but this winter is not consistent with a warming trend at all especially considering this a strong La Nina winter!What you all think about this winter? Is it a blip or a new trend?

Here is an interesting statistic from today:

Tucson, AZ high--35 degrees, low--14.4 (currently 24 @ 10:56pm)
Anchorage, AK high--31 degrees, low--20 (currently 27 @ 10:56pm)

A moment of silence for all the in-ground citrus in Tucson please ......

Peter

In weather conditions which you guys have these days even simple cover means a lot under main cold attack. I did some meassurement today, more here:
link
I've found that 1 square meter of soil surface adds 0.5C (~1F) to temp inside cover in local conditions.
Soil in your area is significantly warmer, I guess that 1 m^2 (~ 3 square feets) could contribute with 1.5C (3F) at least.

It looks like after next week we get a break for all the cold hopefully. For the first 12 days of February the average temperature will likely be about 10F below normal! That is an incredible statistic considering this is a strong La Nina year! Heating degree days will be way way above average especially for the north. The second half of February should be much milder. We shall see.

Bare surface of the earth around the tree should be exposed during the winter months, and there should be nothing on the ground to prevent the sun's heat reaching the soil. To add to ivica's post, wet soil will hold more heat then does dry soil. In winter, dry conditions can actually be more damaging than the cold itself. Cold winter air is usually quite dry, and winter winds can remove water from plants faster than the roots can absorb it. This is especially true for evergreens such as citrus, as water evaporates quickly from their foliage. In addition, if the ground freezes, the underground water turns to ice crystals which cannot be absorbed by plant roots. Even dormant plants need and absorb water year-round.
Water acts as an insulator. Plant cells that are plump with water will be stronger against cold damage. Likewise, moist soil will stay warmer than dry soil, so a regular watering schedule in dry, cold weather can help protect plants from freezing temperatures. - Millet (710-)