A Cold Summer in Porto

Summer is drawing to an end, and it's clear that this has been the coldest summer in Porto in a long time. I've lived in Porto for 15 years, and I've never experienced a summer this cool. Nor can any locals remember such a cool summer.

This doesn't mean that we've been shivering through the summer. The weather has been great. Neither too hot nor too cold. But that's unusual. We normally see temperatures above 30C for prolonged periods, with no clouds to be seen from mid June until late September. This year, we've had a handful of such days with temperatures otherwise hovering between 20C and 25C, and with plenty of clouds and showers.

I first noticed a tendency towards more clouds and lower temperatures some four years ago. The change was too subtle to warrant much of a mention, but it happened in line with a decline in sun activity. We reached a solar minimum last year, and this year has been particularly cool. If this is the beginning of a grand solar minimum, as is generally expected, this weather pattern may well persist. Summers will be like the ones we've had over the last four years, with clouds, showers, and only a handful of really hot days.

If this is indeed due to a change in solar activity, the same logic should apply to other places. Whatever changes in weather patters that have occurred over the last four years will stick. Places that have been hit by persistent drought will see more of this. The same goes for places that have been hit repeatedly by unusual cold, floods and storms. Whatever the last four years have brought will persist.

Should this pan out globally, we can assume that we have entered a new era that will last a few hundred years, corresponding to the normal duration of a grand solar minimum.

Sun

By DracoLumina17 - Own work, CC BY-SA 4.0, Link