Cooling and heating: Cities and FUAs … heating 1981 2010 period in Sliven
Sliven: Cooling and heating: Cities and FUAs … heating 1981 2010 period was -419.34 Degree days in 2025. ◆ Volatile
Cooling and heating degree days - Cities and FUAs — Change in heating in Sliven, 1950–2025
Source: Organisation for Economic Co-operation and Development. Measured in Degree days.
Analysis
The most recent figure for cooling and heating degree days - cities and fuas — change in heating in Sliven is -419.34 Degree days, measured in 2025.
That represents a change of down 13.1% on the previous year and down 48.0% over ten years.
Over the whole period, cooling and heating degree days - cities and fuas — change in heating in Sliven peaked at 456.47 Degree days in 1954 and was at its lowest, -504.6 Degree days, in 2019.
That places Sliven 882nd out of 1314 regions with data for 2025, putting it in the middle of the range.
The series is highly variable year to year, so single readings are best treated with caution.
Cooling and heating: Cities and FUAs … heating 1981 2010 period in Sliven, year by year
| Year | Degree days | Change |
|---|---|---|
| 1950 | -73.53 Degree days | — |
| 1951 | -168.63 Degree days | +129.3% |
| 1952 | -48.97 Degree days | -71.0% |
| 1953 | 255.24 Degree days | -621.3% |
| 1954 | 456.47 Degree days | +78.8% |
| 1955 | -102.36 Degree days | -122.4% |
| 1956 | 423.8 Degree days | -514.0% |
| 1957 | 20.9 Degree days | -95.1% |
| 1958 | -139.3 Degree days | -766.4% |
| 1959 | 153.75 Degree days | -210.4% |
| 1960 | -247.14 Degree days | -260.7% |
| 1961 | -118.74 Degree days | -52.0% |
| 1962 | -15.73 Degree days | -86.8% |
| 1963 | 157.88 Degree days | -1103.8% |
| 1964 | 150.2 Degree days | -4.9% |
| 1965 | 91.84 Degree days | -38.9% |
| 1966 | -278.9 Degree days | -403.7% |
| 1967 | 79.61 Degree days | -128.5% |
| 1968 | -12.82 Degree days | -116.1% |
| 1969 | 314.52 Degree days | -2553.6% |
| 1970 | -97.08 Degree days | -130.9% |
| 1971 | 39.9 Degree days | -141.1% |
| 1972 | 59.94 Degree days | +50.2% |
| 1973 | 266.5 Degree days | +344.6% |
| 1974 | 80.47 Degree days | -69.8% |
| 1975 | 46.63 Degree days | -42.1% |
| 1976 | 151.64 Degree days | +225.2% |
| 1977 | -71.98 Degree days | -147.5% |
| 1978 | 119 Degree days | -265.3% |
| 1979 | -45.82 Degree days | -138.5% |
| 1980 | 186.61 Degree days | -507.3% |
| 1981 | 37.07 Degree days | -80.1% |
| 1982 | 68.37 Degree days | +84.4% |
| 1983 | -0.9513 Degree days | -101.4% |
| 1984 | 62.19 Degree days | -6637.5% |
| 1985 | 190.28 Degree days | +206.0% |
| 1986 | 113.59 Degree days | -40.3% |
| 1987 | 236.77 Degree days | +108.4% |
| 1988 | 174.41 Degree days | -26.3% |
| 1989 | -168.48 Degree days | -196.6% |
| 1990 | -279.36 Degree days | +65.8% |
| 1991 | 188.63 Degree days | -167.5% |
| 1992 | 59.04 Degree days | -68.7% |
| 1993 | 162.64 Degree days | +175.5% |
| 1994 | -214.76 Degree days | -232.1% |
| 1995 | 105.04 Degree days | -148.9% |
| 1996 | 265.37 Degree days | +152.6% |
| 1997 | 220.75 Degree days | -16.8% |
| 1998 | 39.61 Degree days | -82.1% |
| 1999 | -207.84 Degree days | -624.8% |
| 2000 | -140.01 Degree days | -32.6% |
| 2001 | -51.07 Degree days | -63.5% |
| 2002 | -149.52 Degree days | +192.8% |
| 2003 | 219.22 Degree days | -246.6% |
| 2004 | -99.4 Degree days | -145.3% |
| 2005 | 18.83 Degree days | -118.9% |
| 2006 | -22.91 Degree days | -221.6% |
| 2007 | -223.09 Degree days | +874.0% |
| 2008 | -201.85 Degree days | -9.5% |
| 2009 | -218.43 Degree days | +8.2% |
| 2010 | -184.15 Degree days | -15.7% |
| 2011 | 150.66 Degree days | -181.8% |
| 2012 | -30.88 Degree days | -120.5% |
| 2013 | -288.47 Degree days | +834.2% |
| 2014 | -377.01 Degree days | +30.7% |
| 2015 | -283.37 Degree days | -24.8% |
| 2016 | -205.76 Degree days | -27.4% |
| 2017 | -107.59 Degree days | -47.7% |
| 2018 | -235.03 Degree days | +118.4% |
| 2019 | -504.6 Degree days | +114.7% |
| 2020 | -380.21 Degree days | -24.7% |
| 2021 | -184.78 Degree days | -51.4% |
| 2022 | -277.57 Degree days | +50.2% |
| 2023 | -405.49 Degree days | +46.1% |
| 2024 | -370.83 Degree days | -8.5% |
| 2025 | -419.34 Degree days | +13.1% |
Biggest year-on-year movements
Years where Cooling and heating: Cities and FUAs … heating 1981 2010 period in Sliven changed far more than this series normally does. A large move can be a real event or a change in how the figure was measured — the source note below says who published it.
| Year | Change | From | To |
|---|---|---|---|
| 1984 | +6637.5% | -0.9513 Degree days | 62.19 Degree days |
| 1969 | +2553.6% | -12.82 Degree days | 314.52 Degree days |
| 1963 | +1103.8% | -15.73 Degree days | 157.88 Degree days |
Averages by decade
| Decade | Average | Lowest | Highest | Years |
|---|---|---|---|---|
| 1950s | 77.74 Degree days | -168.63 Degree days | 456.47 Degree days | 10 |
| 1960s | 12.07 Degree days | -278.9 Degree days | 314.52 Degree days | 10 |
| 1970s | 54.92 Degree days | -97.08 Degree days | 266.5 Degree days | 10 |
| 1980s | 89.99 Degree days | -168.48 Degree days | 236.77 Degree days | 10 |
| 1990s | 33.91 Degree days | -279.36 Degree days | 265.37 Degree days | 10 |
| 2000s | -86.82 Degree days | -223.09 Degree days | 219.22 Degree days | 10 |
| 2010s | -206.62 Degree days | -504.6 Degree days | 150.66 Degree days | 10 |
| 2020s | -339.7 Degree days | -419.34 Degree days | -184.78 Degree days | 6 |
More reference data data for Sliven
- Cooling and heating degree days by NUTS 2 regions - annual data 5.61 % change on previous year (2025)
- Cooling and heating degree days - Cities and FUAs — Cooling degree 195.56 Degree days (2025)
- Cooling and heating degree days - Cities and FUAs — Change in cooling 56.8 Degree days (2025)
- Cooling and heating degree days - Cities and FUAs 1,825 Degree days (2025)
- Cooling and heating degree days - Cities and FUAs — Change in heating -13.08 % change on previous year (2025)
- Cooling and heating degree days - Cities and FUAs — Cooling degree -39.98 % change on previous year (2025)
- Cooling and heating degree days - Cities and FUAs, annual growth rate -2.59 % change on previous year (2025)
- Cooling and heating degree days by NUTS 2 regions - monthly data -1.7 % change on previous year (2025)
- Cooling and heating degree days - Cities and FUAs — Change in cooling -69.64 % change on previous year (2025)
- Precipitation - Cities and FUAs — Change in extreme precipitation -1.09 Days per year (2024)
Frequently asked questions
- What is cooling and heating degree days - cities and fuas — change in heating in Sliven?
- Cooling and heating degree days - cities and fuas — change in heating in Sliven was -419.34 Degree days in 2025, according to Organisation for Economic Co-operation and Development.
- What is the highest cooling and heating degree days - cities and fuas — change in heating recorded in Sliven?
- The highest recorded value was 456.47 Degree days in 1954.
- What is the lowest cooling and heating degree days - cities and fuas — change in heating recorded in Sliven?
- The lowest recorded value was -504.6 Degree days in 2019.
- How does Sliven rank for cooling and heating degree days - cities and fuas — change in heating?
- Sliven ranks 882nd out of 1314 regions with data for 2025.
- Is cooling and heating degree days - cities and fuas — change in heating rising or falling in Sliven?
- Over the last ten years it is down 48.0%. The long-run trend across the full record is volatile.
- Where does this Sliven data come from?
- The figures come from Organisation for Economic Co-operation and Development, published as part of Cooling and heating degree days - Cities and FUAs — Change in heating degree days from 1981–2010 period to 2020–24 period. Statizoid updates them automatically from the source API.
Download this data
CSV · JSON — 76 observations, free to reuse under OECD Terms and Conditions (attribution required).
About this data
This dataset provides indicators of Cooling and Heating Degree Days (CDDs and HDDs) for FUAs and cities. CDDs and HDDs are measurements used to estimate energy usage based on outdoor temperature. CDD measures the demand for cooling, while HDD measures the demand for heating, both calculated relative to a baseline temperature. Data sources and methodology The indicators use 0.1-degree resolution grids from the ERA5-Land dataset. ERA5-Land is used as it provides harmonised, globally consistent coverage at fine spatial resolution (0.1 degree), enabling the production of comparable subnational indicators also where national meteorological data are not available at the required scale. Annual CDDs are the sum over a year of the differences between the daily mean outdoor air temperature and the threshold temperature when the outdoor temperature is above the threshold temperature. HDDs are the sum over a year of the differences between the threshold temperature and the daily mean outdoor air temperature when the outdoor temperature is below the threshold temperature. Threshold temperatures are set to 22°C for CDDs and 15°C for HDDs. These estimates may differ from official subnational climate statistics due to differences in methodological approaches, such as the use of reanalysis based top down modelling versus in situ observations, along with variations in input data sources, spatial resolution, and the models and algorithms used to generate temperature estimates. Defining FUAs and cities The OECD, in cooperation with the EU, has developed a harmonised definition of functional urban areas (FUAs) to capture the economic and functional reach of cities based on daily commuting patterns (OECD, 2012). FUAs consist of: A city – defined by urban centres in the degree of urbanisation, adapted to the closest local administrative units to define a city. A commuting zone – including all local areas where at least 15% of employed residents work in the city. The delineation process includes: Assigning municipalities surrounded by a single FUA to that FUA. Excluding non-contiguous municipalities. The correspondence table between SAUs and FUAs/cities is available in parquet and csv format. The definition identifies 1 272 FUAs and 1 269 cities in all OECD member countries except Costa Rica and three accession countries. Cite this dataset OECD Regions, cities and local areas database (Cooling and heating degree days - Cities and FUAs), http://oe.cd/geostats Further information OECD Local Data Portal OECD Regions and Cities at a Glance For questions and/or comments, please email CitiesStat@oecd.org