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For many, this time of year is associated with a significant negative shift in mood. It is natural that short blustery days of being homebound gets to the best of us. One needn’t be among the estimated 10 million Americans with Seasonal Affective Disorder to understand the emotions involved. In fact, studies suggest that up to 20% of individuals may suffer a milder form of the disorder. As a psychologist and Pacific Northwesterner with a keen appreciation of daily cloud cover, I empathize. After all, there was a reason the Cullens in the Twilight series were from this area: It was the only place where vampires could thrive.
It is not uncommon in the Pacific Northwest to look at one’s weekly forecast and see the same emoticon day after day unendingly. At left are forecasts for my home city and my dream city. I will not so proudly admit that in my weaker moments, I have opened up the weather app, swiped to other cities, returned to my own, and burst into tears: Why, why, I ask.
But then something curious started happening. My husband and I started noticing the most brilliant (and unforecasted) breaks of radiant sun outside, sunshine so precious in our vitamin D-deficient region that the entire neighborhood seems to come out. Little children head toward the playground in their coats, and all is right in our Norman Rockwell neighborhood. Why, we have wondered, was that left out of the forecast? The mere glimmer of hope for a few hours of sun would be enough to get me through these dismal times. But alas, no such luck in our forecast.
Then I started researching it.
It turns out, there is something called a wet bias factored into forecasts. This explains why the partly sunny emoticon is far more prevalent in San Diego versus Portland. This phenomenon has its own Wikipedia page, which reads:
The term wet bias refers to the phenomenon whereby some weather forecasters (usually deliberately) report a higher probability of precipitation (in particular, of rain) than the probability they believe (and the probability borne out by empirical evidence), in order to increase the usefulness and actionability of their forecast. The Weather Channel has been empirically shown, and has also admitted, to having a wet bias in the case of low probability of precipitation (for instance, a 5% probability may be reported as a 20% probability) but not at high probabilities of precipitation (so a 60% probability will be reported as a 60% probability). Some local TV stations have been shown as having significantly greater wet bias, often reporting a 100% probability of precipitation in cases where it rains only 70% of the time.
Why, one might ask, would meteorologists do this to the public, especially to those with weather already known to be miserable? No one moves to Northern latitudes expecting Caribbean sunshine during the winters, but why not give us a little hope?
According to Nate Silver, author of The Signal and the Noise, The Weather Channel has openly admitted to deliberately exaggerating the probability of precipitation when it is low. This is because of biased incentives: If the correct low probability of precipitation is given, viewers may interpret the forecast as if there were no probability of rain, and then be upset if it does rain. In other words, The Weather Channel compensates for people who have greater loss aversion than they think they do, and therefore miscalculates their cost-loss ratio when it is low, by deliberately inflating probabilities.
While the meteorologists may have their rationale, one might argue the opposite to be true: There is incredible power in instilling hope in the public, particularly in the Northern latitudes. One can’t help but wonder if the wet bias would actually be far more helpful in Southern states. Imagine you plan a day at Disneyland and monsoon-like rains pour down unexpectedly. Wouldn’t you rather have a wet bias for that, instead of in regions where some rain is expected as a daily norm?
Of course, other weather apps are available and many consumers don’t think to install them as they rely on the one already uploaded onto their phone. It wasn’t until this past week, after being regularly fed up with the forecast — and fooled by two beautiful completely unexpected sunny days — that I deleted my default weather app and installed AccuWeather instead. (This is not a sponsored post; I’m not cool enough to be an influencer.) Turns out, this app actually tells you when there is only 30% chance of rain, and that no rain is expected for the next two hours, extremely helpful for those of us hoping to take the dog out for a quick walk without getting soaked.
I feel foolish for not having come to this simple realization earlier. You may not be able to magically conjure the sun during these gloomy winter days, but you can use technology wisely to take advantage of brighter days ahead.
