The Fallacy of Spring

It happens every year.

The spring equinox comes in middle to late March and there is a collective sigh of relief: Winter is over!

Invariably, there are cold spells at the end of March, through April, and occasionally, into May. And without fail, there are people who say something to the effect of, “Doesn’t Mother Nature know that it’s spring?”

Which tells me something about spring: It has a good public relations agent.

Think back to when you learned about the seasons in school. We are taught that spring is the time when the flowers come out, the weather turns warmer, and everything begins anew. How comforting!  Almost like a fairy tale:  We have been released from the evil clutches of Old Man Winter.  It will not be cold anymore!  There’s no way it can snow!

Like most fairly tales, this one is a romanticized dream.

Spring is a battle. It is a battle here in the middle latitudes between the stubborn cold air of the polar regions and the warmer air escaping its sequestration in the tropics. Of course, the warmer air always wins the battle in the end. After all, it has the sun on its side.  But exactly when that battle ends varies from year to year.

With each passing day of the spring, there is a little bit more daylight and the sun gets slightly higher in the sky. This means that, little by little, more heat is coming into the Northern Hemisphere. So every day, the average temperature of the hemisphere goes up a little bit.

But as we say in the science business, the relationship is non-linear at any one particular location in the hemisphere.  Some days, the cold air is very stubborn. Other days, you can imagine that the cold air has been defeated for the season. As a result, occasional big swings in temperature from day to day are to be expected. That is to say, it is perfectly normal.

And like any long, drawn-out battle, there will be relative periods of quiet and relative periods of great turmoil. Those sunny days in the 60s are nice, but there is a reason more tornadoes and damaging thunderstorms happen in spring than in any other season. The battle rages.

Plus, because battles do not end in a day, the notion that “we went straight from winter to summer” is at best, a fanciful one. It never really happens that way, but of course, everyone perceives weather in their own way.

But have faith. As the battle wears on, the grip of the cold air will gradually get weaker and weaker. The great turning point of this battle is the date of the last freeze. From Virginia to southeastern Pennsylvania, that’s normally in middle April.

After a couple of months, the battle usually ends in a quiet whimper. You look around one day in late May or early June and realize you haven’t put on a jacket in a while. Summer always arrives.

Then you can complain about how hot it is.

Farmers' Almanacs - For Entertainment Purposes Only

First of all… which one? There are two, and they are different.

But really, it doesn’t matter if it’s The Old Farmer’s Almanac or just The Farmers’ Almanac.  That’s like choosing between palm readers.

As a general rule, I have no reason to believe any farmers’ almanac. Weather forecasting involves certain physical relationships: thermodynamics, conservation of mass, wave motion, ocean circulations, and other things I would probably never mention on television. Heaven knows we are not perfect, but I think on the large-scale, we do a pretty good job.

Show me the data

How do the farmers’ almanacs do it? They don’t tell.

So why should I trust them? They allude to solar cycles, moon phases, tides. One of them even claims their secret weather forecasting formula is locked away in a box in New Hampshire (for some reason, this makes me hungry for fried chicken).

I’ll show my data to anyone who wants to see it.  But most people don’t really want to see it. They just want to know if it’s going to rain or not.  Is it going to be warm or cold?  Is it going to snow?  How much?

The general public has very little interest in why.  So, if they don’t know (or care), will they be able to tell the difference between someone who tools through the data on a daily basis and a faceless organization generating publicity to sell books?

On a deeper level, it says something about the level of science illiteracy in the country. But I digress.  My friend, Dan Satterfield can run with that one.

To be fair, one almanac mentions that they use climatological records, and they hold firm to the belief that certain weather patterns are repeated over the long-term. I can respect that… it’s called analog forecasting. So I would imagine some of their methodology is perfectly valid, but I cannot verify it, so I cannot trust it.

Amazingly, one of them boasts 80% accuracy. If it were that good, they would all be rich from trading weather-based commodities.  They would have investment banks and energy companies beating down their doors for their data.

And if they are right once in a while?  Well, even a stopped clock is correct two times a day.

How soon we forget. Consider one of the forecasts for summer 2014. Oppressive heat was all the rage. Unless you are on the West Coast, that forecast, as my friend Jason Samenow points out at the Capital Weather Gang, was laughably wrong.

I’m certainly no better. But I don’t pretend to be. This type of forecasting is only in its infancy. Let the buyer beware. 

This post was based on originial blogs from 2012 and 2013, with a small update for 2014.