What an Indian summer!! During the week beginning 26 September, the air reaching the Garden was of a warm source and with unbroken sunshine on several days the temperatures continued to rise. Unfortunately, during this period, the Garden's maximum thermometer was not functioning correctly, so the data used is from the roof of the main AT&T laboratory building in Cambridge, which records:
These are exceptional temperatures for this time of year and long-standing records for individual days have been broken on numerous occasions.
The rainfall total for September 2011 was only 24.9mm which is about half the average, so with this warmth and low rainfall, there are a lot of very dry autumn leaves on the ground.