Mark MadrygaThe accuracy of a weather forecast comes down to data: “Good data and lots of it, plus lots of computing power,” says meteorologist Mark Madryga. 

Around the world, metrological organizations collect information on atmospheric conditions such as humidity, temperature, barometric pressure and wind speeds from a huge variety of sources: satellites, Doppler radar, weather stations, weather balloons, planes in flight, ships at sea, and ocean buoys. Complex computer models crunch those numbers, extrapolating future weather patterns based on principles of fluid dynamics and thermodynamics. 

But even the best models can only make accurate estimates a few days out, Madryga cautions. Long-term seasonal predictions tend to be general, and based on broad historical trends, such as the El Niño and La Niña Pacific Ocean climate cycles.

“On the Pacific coast, when there has been a stronger La Niña, we can look back and see snowier, colder winters,” says Madryga. 

So if long-range predictions are calling for a frosty December, upgrade your home’s weather stripping and watch your savings accrue on MyHydro regardless. But the short-term forecast will tell, with greater precision, when it’s time to break out the extra blankets. And start keeping a close eye on the thermostat.