Dataset: Annual Mean Air Temperature Anomaly at Rothamsted 1878-2019

Citation:  Sarah Perryman, Tony Scott, Chris Hall (2020). Annual Mean Air Temperature Anomaly at Rothamsted 1878-2019 Electronic Rothamsted Archive, Rothamsted Research 10.23637/rms-RMAAtempanomaly-1
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Long-term Temperature Anomaly for Rothamsted, Harpenden, 1878-2019

Long-term Temperature Anomaly for Rothamsted, Harpenden, 1878-2019


Rothamsted has one of the longest running continuous sets of daily meteorological recordings in the world. Temperature has been measured since 1878. The figure above shows the temperature anomaly in annual mean air temperature (black circles), for years 1878 to 2019, relative to the 1878 to 1920 long-term average, which represents the pre-industrial era. Variation in annual temperature is smoothed using an 11-year (132 month) moving average (red line, which removes solar variability and shorter-term variability such as the Southern Oscillation (Hansen et. al., 2010)). The figure shows that air temperatures have risen sharply since 1987 (Scott, 2015) with annual temperatures, over the last decade, estimated to be between 1.3°C and 1.6°C higher than the pre-industrial period (Hansen. et. al., 2016). Much of the rise is due to increases in temperature during the autumn and winter months, and at night-time.


The mean daily temperature is measured over a 24 hour period 0900 to 0900 GMT and calculated from the daily maximum (Tmax) and minimum temperatures (Tmin); the mean daily temperature = (Tmax + Tmin)/2. For each month the mean air temperature is determined from daily data, also the annual mean air temperature for each year (1878 to 2019). The long-term monthly average and annual average for 1878 to 1920 is also determined. The annual mean temperature anomaly and 132 month (11 year) moving average is determined from these annual and monthly air temperature data using Excel functions.

Technical Information

First recorded in 1878, TMAX was originally recorded using a mercury-in-glass with indicator bar minimum thermometer and TMIN using a spirit-in-glass with indicator bar minimum thermometer, both housed in a naturally aspiring temperature screen. Since 2004, temperatures have been recorded automatically by thermistors (electronic temperature probes, Campbell Scientific, Type 107).

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  • Sarah Perryman: Data curator
  • Margaret Glendining: Data curator
  • Andrew Macdonald: Project manager
  • Richard Ostler: Project leader
  • Tony Scott: Data collector
  • Nathalie Castells: Data manager
  • Chris Hall: Data collector

Dataset Access and Conditions

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Rothamsted Research


Creative Commons License This dataset is available under a Creative Commons Attribution Licence (4.0).

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YOU MUST CITE AS: Sarah Perryman, Tony Scott, Chris Hall (2020). Dataset: Annual Mean Air Temperature Anomaly at Rothamsted 1878-2019 Electronic Rothamsted Archive, Rothamsted Research

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Table Of Contents

For further information about the measurement of temperature at Rothamsted see 'Measurements'. For further information about extreme temperature records at Rothamsted see 'Extremes'.

  • The dataset Annual Mean Air Temperature Anomaly at Rothamsted 1878-2019 is a published dataset from the e-RA Database. e-RA is part of the Rothamsted Long-Term Experiments - National Bioscience Research Infrastructure (RLTE-NBRI), which also covers maintenance of the Long-Term Experiments, the Rothamsted Sample Archive and Rothamsted's environmental monitoring activities including the weather stations and its role in the UK Environmental Change Network
  • The RLTE-NBRI is funded by UK Research and Innovation - Biotechnology and Biological Sciences Research Council (UKRI-BBSRC) under award BBS/E/RH/23NB0007 (2023-2028). The RLTE-NBRI is also supported by the Lawes Agricultural Trust. e-RA has been part of a National Capability since 2012, previous awards from the BBSRC were Grants BBS/E/C/00005189 (2012-2017) and BBS/E/C/000J0300 (2017-2022)
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For further information and assistance, please contact the e-RA curators, Sarah Perryman and Margaret Glendining using the e-RA email address: