
According to Icelandic meteorologist Trausti Jónsson, the first 20 days of June 2025 were the coldest start to June in Reykjavík in the 21st century. The average temperature during this period was just 7.8 °C, which is:
- 1.7 °C below the 1991–2020 climate average,
- and 1.5 °C below the average for the past 10 years.
This places the start of June on par with 2001, making 2025 the coldest early June in Reykjavík in 25 years. In contrast, the warmest start to June occurred in 2002, when the average temperature reached 11.5 °C—nearly 4 °C warmer than this year.
Looking at historical records going back to the 19th century, this year’s start of June ranks as the 133rd coldest out of 153 years, with the coldest on record being in 1885, when the average was just 6.6 °C.
Trausti, writing on his Hungurdiskar page on Facebook, expressed disappointment, especially from the perspective of someone who tends plants:
“Naturally, as someone who tends to plants, you want them to thrive and look good. So when something like this happens, it’s definitely a shock.”
The unusually cold weather has likely delayed plant growth, affected gardening and agriculture, and underscored how variable early summer temperatures can be in Iceland—even in a warming world.

Source: https://psl.noaa.gov/cgi-bin/data/composites/comp.day.pl?

Source: https://icelandmonitor.mbl.is/news/news/2025/06/03/june_begins_with_wintry_weather/