Two benchmarks of spring appear to be in conflict with each other this year. From south to north, the ice has been coming off Minnesota lakes at reasonably close to the average dates. However, the elm trees in cities and towns throughout the Red River Valley have been leafing out 10 or 12 days later than average. So based on these two signs, it is difficult to determine if spring weather has been cold or near-average.
In fact, the average daily mean temperature during March was nearly exactly average. April, on the other hand, has been running about 5-6 degrees colder than average. This explains the delay with the elm leaves. Lake ice, it turns out, was much thinner this winter than average due to the deep and persistent snowpack covering the ice all winter. The combination of thin ice and a cold April has resulted in a near-average ice-out this spring.
