How extreme does Portsmouth's weather get?

The hottest, coldest, wettest and snowiest days Portsmouth has recorded — the outer limits of what its weather can do, and how far they sit beyond a normal day.

Based on 20 years of daily weather observations (2005–present), from the Melville Hall Airport station 18 km away. Updated through August 2025 — an all-time extreme only changes when a more extreme day actually occurs, so some dates are old. That is normal, not stale data.

The four kinds of extreme

The hottest, coldest, wettest and snowiest single days Portsmouth has recorded — each shown against what a normal day that time of year looks like.

🔥 Hottest day

99°F Jun 30, 2006

The three most extreme on record

1 99°F Jun 30, 2006

2 99°F Jun 14, 2011

3 99°F Aug 8, 2023

❄️ Coldest night

59°F Jan 14, 2014

The three most extreme on record

1 59°F Jan 14, 2014

2 64°F Mar 14, 2013

3 64°F Mar 15, 2013

🌧️ Most rain in one day

9.91 in Nov 7, 2022

The three most extreme on record

1 9.91 in Nov 7, 2022recent

2 9.15 in Sep 18, 2022

3 8.13 in Oct 1, 2022

In plain terms

Across the record, Portsmouth has reached as high as 99°F and as low as 59°F. A single day has delivered over 10 inches of rain. Those are the outer edges worth knowing if you are moving here, planning a trip, or thinking about a house.

Methodology & sources

Temperature — modelled for this location from ERA5-Land reanalysis, a ~9 km global grid, because no long-record weather station is close enough to use.

Precipitation — 1991–2020 normals computed from 10 years of daily observations at LE Lamentin, a weather station, about 121 km from the city centre. The underlying daily records come from NOAA's global station network.

How we build these numbers →

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