Longer Days Ahead
2016-03-19 20:48:44.000 – Michael Dorfman, Weather Observer/IT Specialist
With the first day of spring coming up (tomorrow!), I decided to get a bit excited about the warm temperatures we’ll see on the summit mid-summer. While it may not seem that warm to valley-dwellers, our record warm temperature recorded on the summit is a balmy 72F degrees (which was recorded twice in our history).
In celebration of the coming warmth, I’ve put together some numbers from the summit. The graph below shows average temperature and relative humidity compared to wind direction from our digital sensors since 2005. While this doesn’t hold true for every situation, you can generally predict what type of air mass you’ll see based on the direction it comes from. When we see prevailing winds from the north, we’re likely to see cold (from higher-latitude Canada) and dry (from above a continent) air mass. Temperatures and relative humidity soar when we have a flow from the east through southwest, as we see air from more southern latitudes and air that originates over the ocean.
I also decided to dig up some of our 30-year average monthly temperature stats and have compared them with the length of day in the diagram below. As you can easily see, our temperature and length of day do not directly correspond to each other; our longest day in June occurs a month before our warmest temperatures in July.
The National Weather Service explains this phenomena with relative clarity:
“There is a lag between the longest day of the year and the warmest average temperatures for most mid and high latitude locations.
Michael Dorfman, Weather Observer/IT Specialist
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