Portsmouth Weather in May
May in Portsmouth sees daytime temperatures around 19°C (66°F) and lows of 8°C (46°F) at night. With around 116 mm (4.6 in) of rainfall expected, it's worth packing a rain jacket.
Rainfall in Portsmouth in May
You can expect rain on around 12 days based on historical patterns, with 116 mm (4.6 in) average for the month. Individual showers can be quite heavy this month. A proper umbrella or rain jacket is worth having.
Temperature in Portsmouth in May
Daytime highs in Portsmouth in May reach 19°C (66°F), with nights around 8°C (46°F). This creates a mild day-to-night pattern that is generally easy to manage with the right clothing. At 8°C (46°F) overnight, it gets properly cold after dark. On the bright side, cold nights tend to make for excellent sleeping conditions.
Sunshine in Portsmouth in May
There are approximately 258 hours of sunshine this month, resulting in mostly clear days.Our weather planner can help you find worldwide destinations with pleasant weather during this period. September typically offers the best weather for Portsmouth.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Portsmouth's climate page.
Portsmouth Temperature in May
Min Temperature
8°C (46°F)
Max Temperature
19°C (66°F)
Chance of Rain
41%
Precipitation
116 mm (4.6 in)
Rainy days
12 days
Humidity
65% *
Sunshine
258 hours *
Percentage Sunshine
*
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Portsmouth typically rise from around 17°C (63°F) at the start of May to approximately 22°C (72°F) by the end. Nights are cool, with lows typically ranging from 6°C (43°F) to 11°C (52°F).
Average temperatures in May
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in May
Historical weather for Portsmouth in May
Browse day-by-day weather records for Portsmouth spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Portsmouth historical weather extremes in May
The extremes listed below come from historical weather data collected in Portsmouth from 2001 through 2026.
- On May 31, 2013, temperatures climbed to 34°C (93°F), marking the warmest May day on record.
- On May 9, 2020, Portsmouth saw its coldest May day with temperatures maxing out at 6°C (43°F).
- Nighttime temperatures dropped to -3°C (27°F) on May 7, 2001, marking the coldest May night on record.
Best Places in the United States of America in May
Find out more about the weather in the United States of America and which places have the best travel conditions in this month. See all of the United States of America in May →
perfect weather
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unpleasant
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What to Wear in Portsmouth in May
Pleasant temperatures in May mean you can pack light but flexibel pieces. Think cotton t-shirts, comfortable walking shorts, and one warmer layer for evenings. A light sweater or denim jacket works well. Prepare for significant rainfall with proper waterproof clothing and shoes. And with plenty of sunshine hours, don’t forget sunglasses, sunscreen, and maybe a sun hat.What To Do in Portsmouth in May
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Portsmouth's climate page.
Temperature Rainfall Sunshine Humidity
See the full Portsmouth climate overview or explore weather in the United States of America.
