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1927 Map of the Arboretum

Weather Data at the Arnold Arboretum

Collection of detailed weather data has been an ongoing interest at the Arnold Arboretum for nearly a century. Over the years, various departments and members of staff have observed and documented weather on the grounds, particularly in terms of plant hardiness, microclimates, seasonal plant phenology, and extreme weather events. Collection procedures have ranged from daily handwritten observations to today’s highly automated systems that broadcast live weather data online.

The study of weather at the Arboretum developed through an interest in how meteorological conditions (particularly temperature) can affect the flora inhabiting our landscape. In Alfred Rehder’s original publication of the Manual of Cultivated Trees and Shrubs (1927), the first Arnold Arboretum Hardiness Zone Map for the US was created to help inform the public about the limitations of plants in surviving minimum cold temperatures. Donald Wyman and other Arboretum staff periodically updated these maps, which were featured in various publications.  In 1960, the USDA published their first standardized national Plant Hardiness Zone map; most recently updated in 2012, it is still considered to be the most reliable source of plant hardiness information.

Staff began recording weather data in 1965 from a weather station installed at the Dana Greenhouses, a practice which continues today. In early winter 2011, a new weather station was added at the Arboretum at the Weld Hill Research Building. With the ability to report and share information online, precise weather data can now be obtained by anyone with access to a computer or mobile device. This diagnostic tool is a useful resource for staff and the visiting public, providing a highly localized and robust picture of our weather.

The application of these data can inform horticultural management strategies, enhance record keeping, and facilitate comparisons with field observations. The station utilized by the Arboretum features a highly modular design allowing for seamless integration of a wide variety of climatic sensors. Currently these sensors monitor temperature, relative humidity, barometric pressure, rain, leaf wetness, solar radiation, soil temperature, and wind speed and direction.

In addition to our central weather station, the Arnold Arboretum gathers data from 18 micro-stations dispersed throughout the landscape. These micro-stations were installed in 2008 to help identify microclimates on the grounds. This information is highly valuable for both mapping climate patterns over time and for locating areas of the landscape where plants of marginal hardiness may be sited to improve their chances of survival.

Hourly and summary data since 2020 is publicly available for download on the NEWA website. The Arnold Arboretum weather station is called “Boston (Weld Hill), MA”.

Current weather conditions, weather data for the current week only, and all data collected since August 2020 are publicly available for direct download from the HOBO link. Weather data is collected every 5 minutes. For data collected prior to August 2020 see link below.

Weather data collected every 5 minutes from Feb 2012 to August 2020 is publicly available for download. For weather data since August 2020, see current weather above.

Download an excel file of historical weather data collected between 1896 – 1946.

More weather resources:

  • Al Fordham’s Arnoldia article on weather/climate provides a summary of Hugh Raup’s data from the 1934/5 winter [pdf]
  • Michael Dosmann’s 2015 Arnoldia article on microclimates at the Arnold Arboretum [pdf]