Cold, cold year?

Summer of 2021 will go down as the warmest since records began, but in Poland it was just slightly warmer than long-term average. Although June (thanks to its hot second half) and July were markedly warmer even in comparison to 1991-2020 reference period, August tilted the balance of the entire summer towards just “a bit warm” category.

With temperature averaging out +17.2C it was the coldest August in Warsaw since 2005 (+17.7C then) and the third-coldest in my lifetime, after August 1998 (mean temperature: +16.4C) and August 1993 (+16.6C). My parents remember six Augusts between 1976 and 1981 when average temperatures in Warsaw were ranging from +15.8C to +16.8C. In recent August there was no spell of exceptional cold (month-time low of +7.3C, while on average the lowest temperature in August is +7.8C), but on 12 days temperature did not top above +20C. Rainfall was also in abundance – monthly precipitation reached 166 millimetres, vs. long-term average of 61 millimetres (and was short of post-WW2 record by 13 millimetres).

September has been partly making up for the cold August, offering plenty of sunshine and day-time highs of +25C recently. Forecasters say the coming week should bring clement weather with temperatures peaking just below +20C. Preliminary forecasts for next months suggest October should bring above-average temperatures and Indian summer, while November is to be warm, but wet.

I wonder whether 2021 will be the first “cold” year since 2010. Until now, the year-to-date negative temperature deviation in Warsaw stands at some - 0.3 Celsius degree. If the trend continues, 2021 stands a chance to be the coldest since than 2010 (mean: +7.9C). So far four months (February, April, May, August) brought below-average temperatures. More than four months with below-average mean temperature in Warsaw were reported during my lifetime in 2003, 1996, 1991 and 1991. Everything depends now on the weather in the fourth quarter. But do not date to confuse weather for the climate. Just like one swallow does not make a summer, one colder year in just one part of the globe does not deny the continuing global warming.

Next post in two weeks (off for a wedding next weekend, hoping not to catch the Delta).