Much of the earliest planted wheat in the Red River Valley is approaching the 5 leaf stage. At this time the initiation of the head has begun. After the number of tillers that were initiated over the past three weeks, the number of spikelets is the second the three yield components that ultimately will determine yield. Like tillering, the number of spikelets is also greatly influenced by temperature. The figure below show what happens as the average maximum temperature increases from 65 to 85; the average spikelet counts declines almost by a third from 17 to 13.
Although cooler daytime temperatures would be desirable to maximize the yield potential, you shouldn't be completely discouraged or disillusioned. The beauty of wheat is its great ability to compensate between yield components. If the conditions during anthesis and grain fill are favorable for wheat the crop will put its energy in additional kernels per spikelet (3 to 4 rather than 2 to 3) and larger kernels.