This Date In Weather History: Snow In Denver? In July?

DENVER (CBS4) - We know it's not uncommon to see summer snowfall high in the Rocky Mountains of Colorado, but what about in Denver?

On July 17, 1872, a weather observer with the U.S. Army Signal Service recorded a rare summer snowfall during the early morning hours in his hand written weather journal.

He wrote that rain began at 1:30 a.m. and changed over to snow around 3 a.m. for about 30 minutes before changing back to rain.

This is the only documentation of snowfall in Denver during the month of July.

The report is not included in Denver's official snowfall records because the weather station didn't begin until Jan. 1, 1882.

One would initially think the journal entry was an error because the low that morning was 45°F.

But it's just a great example of how the surface temperature only determines what happens to the snowfall once it lands.

While the surface can be above freezing, it can be sufficiently cold enough for a light stratiform snowfall in the clouds just above.

Meteorologist Chris Spears writes about stories related to weather and climate in Colorado. Check out his bio or follow him on Twitter @ChrisCBS4.