Portsmouth New Hampshire Climate Data

Monthly Average Climate Data for Portsmouth New Hampshire

Switch Data to Fahrenheit
MonthAvg. LowAvg. HighAvg. Precip
January-8.7 °C1 °C91.69 mm
February-8.1 °C2.4 °C91.19 mm
March-3.7 °C6.5 °C112.01 mm
April1.7 °C13.1 °C115.57 mm
May7.3 °C18.7 °C98.55 mm
June12.7 °C23.9 °C107.7 mm
July16 °C27.2 °C92.96 mm
August15.3 °C26.7 °C82.55 mm
September11.3 °C22.5 °C96.52 mm
October4.9 °C15.7 °C126.49 mm
November-0.2 °C9.8 °C100.33 mm
December-5.1 °C4 °C113.28 mm
Annual3.6 °C14.3 °C1228.84 mm

Climate Data for Portsmouth New Hampshire

Average First Frost DateOct. 1 - Oct. 10
Average Last Frost DateMay 21 - May 31
Average Days With Frost125-150 Days
Plant Hardiness Zone - 2023Zone 6a : -23.3°C to -20.6°C
Plant Hardiness Zone - 2012Zone 6a : -23.3°C to -20.6°C
Current Drought ConditionsNormal
Köppen Climate ClassificationDfb - Humid Continental Mild Summer, Wet All Year
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