I’ve received a lot of questions and comments about the link between colder-than-normal springs and summer conditions.
Some people believe that cold springs mean warm summers, mainly based on what happened last year.
So look at the data and find out!
Let’s start by plotting spring temperatures (March to May) in Washington State using the NOAA Climate Bureau dataset over the past century (through 2022). Warmer earlier during this period, then cooled in the 1950s-1970s and then warmed back to previous levels over the past decades.
I then identified the ten most interesting springs.
Next, I identified the top ten coolest springs and plotted their anomalous (different) temperatures relative to normal (the average for the period 1991-2020) for the summer (July-December). September)– below.
So, based on climatology, there’s no reason to expect a warmer than usual summer…in fact, quite the opposite.
But what about seasonal forecasting models, such as those run by the European Center? Below is a forecast for surface air temperature anomalies from normal for July to August. Very close to the normal conditions being predicted.
Canada’s seasonal pattern is, in general, pretty good, similar to Central Europe (see below). Almost normal for our area.
In contrast, the American Model (CFSv2), which is often not as clever, has summers that are 0.5 to 2C warmer than usual.
Key point:
At this point, there’s no good reason to expect a warmer-than-usual summer in this Northwest. In terms of climate, cold springs do NOT tend to lead to warmer-than-normal summers, if at all, vice versa. The best season models show near-normal temperatures from July to September.
And I can’t help but note that our skills in seasonal forecasting, especially for the summer, are generally quite poor. Meteorologists have come a long way with short-term weather predictions, but our seasonal capacity is something we need to be extremely modest about. 😇
