Groton-New London Arpt climate by month
Averages and records for each calendar month at Groton-New London Arpt, United States, from 1999 to 2026. The warmest month is July, averaging 26.5°C; the coolest is January at 3.5°C.
| Month | Avg high | Avg low | Record high | Record low | Years |
|---|---|---|---|---|---|
| January | 3.5°C | −4.9°C | 18.9°C12 January 2020 | −21.6°C16 January 2009 | 27 / 27 |
| February | 4.6°C | −4.4°C | 21.7°C16 February 2023 | −22.1°C14 February 2016 | 27 / 27 |
| March | 8.5°C | −0.7°C | 23.3°C18 March 2011 | −15.5°C6 March 2015 | 27 / 27 |
| April | 13.6°C | 4.0°C | 30.0°C26 April 2009 | −5.5°C2 April 2019 | 27 / 27 |
| May | 18.4°C | 9.2°C | 33.9°C31 May 2022 | −1.0°C1 May 2008 | 27 / 27 |
| June | 23.3°C | 14.5°C | 33.9°C25 June 2025 | 4.4°C1 June 2001 | 27 / 27 |
| July | 26.5°C | 18.3°C | 38.3°C6 July 2010 | 10.0°C11 July 2002 | 27 / 27 |
| August | 26.3°C | 17.8°C | 33.9°C14 August 2016 | 8.3°C21 August 2000 | 27 / 27 |
| September | 23.1°C | 13.9°C | 32.2°C4 September 2018 | 2.2°C29 September 2000 | 26 / 27 |
| October | 17.5°C | 7.9°C | 30.6°C2 October 2019 | −4.3°C19 October 2015 | 26 / 26 |
| November | 12.1°C | 2.4°C | 26.1°C7 November 2022 | −11.0°C23 November 2018 | 26 / 26 |
| December | 6.7°C | −1.8°C | 18.9°C1 December 2001 | −14.4°C20 December 2004 | 26 / 27 |
Years shows the number behind the average high, then the number holding a record for that month. They differ because a year contributes an average only when the month has at least 25 days of readings, while a single reading is enough to set a record. The average low is withheld on the same 25-day rule and is counted separately again; it is shown as a dash where the archive cannot support it. Across the twelve months here the averages rest on 26 to 27 years each.
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Every figure on this page is computed from NOAA GHCN-Daily observations stored per station, per year, per month. Nothing is modelled, interpolated or estimated, and a month the archive never covered is left out rather than filled in. A station appears here only once all twelve months carry an average from at least 10 years. See how this is built.