Of all the problems which plague the concrete contractor, none is so persistent, nor so disastrous at times as the weather. And strangely enough, there is no problem involved in his operation of which the contractor has less specific knowledge than the weather. There are five elements of weather with which you should be passingly familiar with in order to make an educated guess on what tomorrow will bring. They are: clouds, wind, barometric pressure, temperature, and fronts. In interpreting cloud formations, altostratus and stratocumulus clouds moving in usually precede a cold front and bring rain or snow with them. Cirrus and cirrostratus clouds, followed by a thick layer of altostratus, usually presage the coming of a warm front and bring rain. For wind, a sudden and precipitate shift in wind speed is the indicator of an approaching shift in the weather; when a steady, unexpected breeze begins to blow, watch for changeable weather. If there is a steadily rising trend showing on your barometer, this usually indicates clearing skies; conversely, falling pressure means a spell of approaching bad weather. Usually, temperatures will raise slightly just before a storm, with this tendency more pronouced in the winter. A weather map is needed in order to interprete fronts. A cold front is likely to pass with gusty winds, haeavy cumulus clouds and scattered precipitation, with reasonalby clear weather behind it. A warm front will likely bring steady precipitation and be followed by cloudy, lowering skies. And a occluded front results in high winds, heavy precipitaion, and generally bad weather .