woke up to a low of 40 this morning

Perfect chilling weather. Remember once it drops below 32 degrees, it doesn't count. It has to be above 32F.
A huge cold spell is coming, so January doesn't look as nice. So little chance of meeting chilling requirements in January. This winter has a chance of being colder than the last. That is what is predicted anyway. Watch what you ask for. We have been cooling for the last 18 years and looks like no break in the trend. According to NOAA and NASA satellite data anyway.

Here is a link that might be useful: The very long cold spell

This post was edited by Drew51 on Mon, Dec 22, 14 at 13:08

I'm running way warmer than KS and so far chilling is probably near normal. Cloudy wet weather in KS would be good chilling weather. If clouds hold nights around 40 and days aren't too warm, you'll get lots of chilling.

You can check how you are doing with the Get Chill model linked below. You'll need a nearby weather station off weather under ground, one that has good data, some don't.

As of Dec 20 I had 383 hrs below 45 and 289 Utah. That compares to 1062 below 45 and 343 Utah all last winter.

If you have 400-500 Utah to date you're apples will do fine.

Here is a link that might be useful: Get Chill

Heat stress over 20C.? Ha! Try 43C. (which many apples tolerate just fine, including their beloved Bramley).

It appears now the critical temp range is 32-45, correct? Outside that range doesn't count?

I can look up NWS NowData daily high and low temps but won't be able to glean from it the actual number of hours in a given range, hope the Get Chill model deals with that. Thanks to you both for your responses. Oh, lucky me, the NWS data for my location is taken less than 1/4 mile away from my trees. I've compared it to my orchard thermometer many, many times and it agrees with the orchard thermometer in my orchard. My tax dollars at work in a good way.

I too am running warmer than normal for December. I wish, at least, some of these cool weather predictions were true. Dennis had me believing we were to have a white xmas, but I just checked my 10 day outlook and it doesn't look like any chance of snow. Only 1 time does it drop below freezing at night and even then it calls for a low of 29.

More like November than December here.

michael:

For apples I like the Utah model. For that model best chilling is at 40-43F, none below 32 or above 60. In fact above 60F you need to subtract one hr per hr. 36-54F is the sweet spot.

In summary Utah model is 1 hr chilling/hr at 40-43F falling to 0.5 hr/hr at 36 and 54F, and -1hr/hr above 60F.

See left curve in fig 4 below.

Here is a link that might be useful: Utah chill model function in fig 4

fruitnut my numbers today are 327 below, between 294, utah mod 114. I am hoping for cooler weather in jan. Today in 70's last night near 70. Apple trees never lost leaves. Peach looking like they are getting ready to sprout. figs putting on new leaves. What numbers are more important below,between or utah last year had a cold winter

Now I'm wondering if there are any mathematical models that allow one to interpolate DDs bases on the highs and lows since I have the high low data. Without a data logger set to sample temp every few minutes, how does one accurately determine the number of DDs accumulated within a certain range?

The Get Chill model does all that for you. All you need is good data from a station nearby. Go to Get Chill link above which will direct you to nearby stations. Type in station ID and it spits out chill units based on 4 different models.

Thanks, tried the get chill link model and came up with 0 hrs.........hmm. The wundermap allowed me to enter my NWS Station number but the nearest wundermap location was about 30 miles away which is useless. Wondering if the model did anything with the NWS ID number.