Do Winter & Summer “Freeze Together?” Weather Myth EXPOSED

Each year in Iceland, the first Thursday after the 18th April each year is the official beginning of the summer, marked by a national holiday. That’s today! Happy summer.

According to a well-known Icelandic legend, if the eve of this holiday suffers frost, the seasons are said to have “frozen together,” signifying a warm summer and a good harvest ahead.

Folklore vs. science

There’s seemingly no definitive root or reasoning behind the “freezing together” myth, although it’s thought to predate Christianity in Iceland, possibly going back as far as the 11th century. Back then, Iceland ran according to the Norse calendar, which had only had two formal seasons—winter and summer.

We called up Icelandic folk historian Árni Björnsson, who said: “We first see this legend written about in the 19th Century by Jón Árnasson, the collector of Icelandic folk tales. But we don’t know how long it was believed before then.”

To find out if it’s true, or if there’s any historical correspondence between a frosty final night of spring and a warm summer, we called Elín Björk Jónasdóttir—the coordinator of general forecasting at the Icelandic MET Office, vedur.is. “The ‘freezing together’ myth has been rebuffed numerous times,” says Elin. “I don’t know why this myth started, but the real reason that we often have freezing temperatures happen at this time of year is the clear skies, which mean there’s a lot of outgoing radiation. Also, it tends to be calm, which people might think suggests calm weather ahead. But mostly, I think it’s wishful thinking.”

No statistical basis

Elin points to an article by meteorologist, researcher and weather blogger Trausti Jónsson, which shows a graph of years when summer and winter should have frozen together, according to the myth.

“Trausti’s blog shows that it’s not a particularly true myth,” says Elin. “He took the average minimum temperature in Reykjavík the night before the summer began, and compared it to the average temperature that summer. The results were that 20 summers that went below freezing on this night went on to have a below average temperature, and 13 summers were above average. So the evidence we have says there’s no statistical basis for this.”

Grapevine’s ruling? Well, it wasn’t below zero last night in Reykjavík (although it was in the blue parts of the map above). So, just in case, we’re choosing not to believe this particular myth.

This year, at least.

Additional research by Paul Fontaine.