Seasonal lag: Why warmer temperatures occur well after summer solstice
It's summer in the Last Frontier and days are slowly getting shorter. While that may be the case, have you ever noticed that the warmer days actually don't happen until several weeks after summer solstice?
The answer lies in our oceans — which make up 71 percent of the Earth's surface — and how long it takes for water to heat up, which creates what is called seasonal lag.
The ocean is a vast resource that not only plays a huge role in keeping us alive but in warming the Earth's atmosphere. We are nearly through with the month of June and not only are we dealing with potential record warmth through the rest of this week, but our warmest days in Anchorage have yet to arrive.
Seasonal lag is when you experience the hottest and coldest days of the year well after the official start of each season.
Imagine if placing a pot of water on the stove and heating it up, it doesn't automatically get hot. In fact, it can take a good 10 to 15 minutes before the water even begins boiling. This is because water has a higher heat capacity than land, meaning it takes more heat to raise the temperature of the water than it does to heat the land.
Even after you have turned the burner off on the stove, the temperature of the water continues to rise slightly because there is still some heat being added by the hot burner. Temperatures continue to rise until equilibrium is established, as the heat being added equals the heat that is leaving.
Equilibrium is usually achieved through weather events like hurricanes and thunderstorms working to distribute heat evenly across the globe.
While Alaska has a fairly comfortable climate, we usually don't see our warmest days until late in July because the sun has to warm the oceans the same time it melts ice and snow still blanketing some mountaintops. It's for this reason that the coldest days of the year are experienced well after winter has started because water takes longer to cool off than land.
So what does this mean for us?
While our warmest days are still ahead, we won't see sweltering heat due to our location in the Northern Hemisphere, but we can expect to gradually see the thermometer climb into the 70s. On average Anchorage sees at least 17 days each year with highs greater than or equal to 70 degrees. With only 6 days over 70 degrees recorded so far this year, we may certainly still have our fair share of summer to experience.
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