Air temperature anomalies in experimental forests in Rogów in 1924–2015*

Meteorological measurements, that aim to monitor weather and climate conditions to aid research in changing forest ecosystems, have been conducted in the Warsaw University of Life Sciences' experimental forests in Rogów since 1924. Based on the long-term air temperature measurements, it can be demonstrated that in the years 1924–2015, anomalously cold months have occurred less often (ca. 3.2%) than anomalously warm months (ca. 4.5%). During the last 20 years, only two anomalously cold months were recorded (November 1998, December 2010), whereas anomalously warm months occurred frequently (May 2002, July 1999, 2002, 2006, 2010, 2012, 2014, August 2002, 2015, September 1999, 2006, October 2000, 2001). We hypothesised that the more frequent anomalously warm months would constitute a trend in increasing the air temperature for particular months between 1924–2015, but surprisingly, a statistically significant trend was observed for all winter (XII–II) and spring months (III–IV) as well as the end of summer (VIII).