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Personal home weather stations from companies like La-Crosse Technology, Oregon Scientific and Davis Instruments help growers and homeowners get a better view of their weather on a more one-on-one basis. But not everyone wants to go that route.
So, how can a commercial grower or even a local gardener use the weather bureau forecasts to their best advantage? Let’s take one phase to see what we can do with a weather forecast and a thermometer to calculate your micro-climate temperatures.

• When you hear on the weather report that the low last night was 40° did your thermometer stand there at day break?
• Does your thermometer generally differ from the official temperature?
• ls it generally higher? How much?

Your thermometer should be hung where the air can get around it without obstruction, yet be in the shade.

Suspend the thermometer in an box or a crate and attach the box to a post 15 or 20 feet from buildings. The open side of the box should face north so the daytime sun cannot get in.

Here are some of the things that make a difference between your temperature reading and the official one.

First, is there a wind?

You will find that the more wind, the closer your thermometer will read with the official. If the wind is calm, there may be a bigger difference. The second factor that makes a difference is the amount of clouds. On a cloudy night the earth has a blanket of sorts which keeps the temperature from falling too fast. A third factor you must consider is the condition of the soil.

Is the ground wet or dry or covered with snow? Snow will cool the fastest, dry soil next and wet soil slowest during the night.

Keep a Weather Chart

Conduct an experiment to find out just how the temperature of your micro-climate differs from the official temperature recorded at the weather station.

Create a simple chart so you can keep a record for a month or so.

Record the following information daily and try to record the data about the same time.

• Cloudy Night – Party Cloudy – Clear
• Soil – Wet or Dry
• Light wind
• Moderate wind

We have three choices as to whether the sky was cloudy, partly cloudy, or clear during the night, was the soil is wet or dry, and finally a choice of whether the wind during the night was calm, light, or moderate. After you have figured out what kind of a night you had, compare the low temperature at your location with the one given by the weatherman. Stick to one source for the weather forecast like the weather station.

Some Samples

Let’s take a couple of samples. It has been rainy, cloudy, and blowing all night. You read 38° on your thermometer and the weatherman says it was 42°. Enter a -4 in the section for cloudy night, wet soil, moderate wind (example A). The next night it is partly cloudy, the ground is wet, and the wind is light. The thermometer on your post reads 41° and the official thermometer is 46° then you would put -5 on the chart as shown in (example B).

Keep this chart until you get at least 10 values in each box, then average them as we have done in the example below (example C). You’ll soon be able to make the official temperature apply to your garden and micro-climate.

Download the weather chart spreadsheet here: