Climate monitoring information on the webpage of HungaroMet to raise awareness on climate change and support the decision-making

One way for monitoring climate change is to compute and analyse the different extreme climate indices. At the Climate Research Department of the Hungarian Meteorological Service, we have implemented climate stripes, several warm climate indices and some of the cold indices for 24 municipalities and for the country as a whole from the beginning of the last century. Homogenised (MASHv3.03 software) daily data were used to derive the yearly climate indices values. We used interpolated data (MISHv1.03 software) for getting the countrywide averages. The trend line fitted to the annual data indicates the slope of change, its magnitude and significance with 90% confidence is depected too on the graphs. By clicking on the figures, the municipal graphs can be displayed and downloaded freely from the webpage of HungaroMet: https://www.met.hu/eghajlat/eghajlatvaltozas/megfigyelt_hazai_valtozasok/
An obvious effect of climate change in our region is the increase in the frequency of extremes associated with high temperatures, the persistence and intensity of heat waves. Graphs of very hot days (Tmax ≥ 35 °C) and hot days (Tmax ≥ 30 °C) illustrate the recent changes for the county seats.  The current practice of issuing heat alerts in Hungary is that National Centre for Public Health issues an alert following a warning published by the Hungarian Meteorological Service. Time series showing the number of days per year corresponding the conditions for the different heat alert levels (level I: Ta ≥ 25 °C, level II: Ta ≥ 25 °C for at least 3 consecutive days, level III: Ta ≥ 27 °C for at least 3 consecutive days) are also available for download. The "climate mosaic" not only shows the heat and heatwave trends on an annual basis, but also illustrates the heat periods in a matrix-like arrangement, their frequency and duration can be tracked on that.
Regarding the cold climate indices, the number of frost days (daily minimum temperature ≤ 0 °C), number of days with a minimum daily temperature ≤ -10 °C, number of winter days with daily maximum temperature ≤ 0 °C day, longest frost period (maximum length of consecutive frost day), number of cold days with daily minimum temperature ≤ -5 °C, annual sum of heating degree-days, days according to Extreme Cold Warning Level I-II-II (minimum daily temperature < -15 °C,  -20 °C and -25 °C) are visualized.
We hope that this information is supporting the development of municipal climate change strategies and action plans.

Acknowledgements:
The research presented was carried out within the framework of the Széchenyi Plan Plus program with the support RRF-2.3.1-21-2022-00014 Climate Change Multidisciplinary National Laboratory project.