BHO Climatological Data (1885 - Present)
This monument at Blue Hill was erected in 1912 in memory of the Observatory's founder,
Abbott Lawrence Rotch. At the centennial of the Observatory, the stone was etched with
a summary of the first 100 years of climate data. Among the extremes that have been
established since 1985 are the greatest annual rainfall of 71.00 inches recorded in 1998
and the greatest seasonal snowfall of 144.4 inches measured in the winter of 1995-1996.
Long-Term Climate Data Graphs
The annual mean temperature plot below includes 1831-1884 data from nearby locations,
which have been carefully adjusted to the Blue Hill summit location, to extend the
Observatory mean temperature record back to 1831.
Annual Mean Temperature
Annual Mean Wind Speed
Monthly Climate Data Graphs
Note that departures from the mean in these plots are calculated with the 1891-2000
long-term average, which is much less variable than recent 30-year "normals".
(Last updated 1 February 2009)