The county has experienced its driest year since 1921, with rainfall on or above average in only two months of 2011.
The annual weather report, compiled by Mike Lewis, manager of Pitsford Hall Weather Station, showed that a total of 399.5mm of rain fell in Northamptonshire last year, which is two thirds of the expected amount.
Mr Lewis said: “The notable feature of the weather in 2011 was the lack of rainfall.
“Only two months in 2011 saw rainfall come in at close to or above average – February with 51.9mm and July with 47.4mm. March and April were the two driest months with just 4.8mm and 7.4mm falling respectively.
“Last month saw a continuation of below-average rainfall with 47.4mm, although with 18 rain days and 13 wet days [when more than 1mm of rain is recorded], December’s total ensured the 1921 recorded remained unbroken.”
Due to the exceptionally dry 2011, water companies have already warned people to be prepared for possible drought conditions this year. Water levels at Pitsford Reservoir have dropped to only half full, forcing the Environment Agency to issue the supplier with a permit allowing water to be taken from the River Nene. Anglian Water will be allowed to top up the reservoir until March 31 if necessary.
The 2011 weather report also shows that it was the ninth warmest year on record, with an average temperature of 11.1C. The highest temperature was 29.4C on June 27 and the lowest was -4.4C on January 31.
There were only three days on which it snowed and only two when snow lay on the ground.
Mr Lewis said: “This contrasts with 2010 when snow fell on 39 days and lay for 18. In fact, 2011 saw the least amount of snow at Pitsford since records began at this site in 1998.”
February was both the windiest and wettest month, with 51.9mm of rainfall and winds with an average speed of 8.1mph.