Portsmouth
New Hampshire, USA
Long-term weather forecast
Long-term weather forecast

October weather forecast and climate
Portsmouth, NH

Bright neon lights and buildings next to the very calm waters of the iconic Piscataqua River in Portsmouth, New Hampshire, the clear dusk sky in close up view
Bright neon lights and buildings next to the very calm waters of the iconic Piscataqua River in Portsmouth, New Hampshire, the clear dusk sky in close up view
October, the same as September, in Portsmouth, New Hampshire, is a moderate autumn month, with temperature in the range of an average low of 41°F (5°C) and an average high of 59°F (15°C).

Temperature

In Portsmouth, the average high-temperature in October decreases, from a pleasant 70°F (21.1°C) in September, to a mild 59°F (15°C). The average low-temperature, in October, is 41°F (5°C).

Rainfall

In Portsmouth, in October, during 9 rainfall days, 3.7" (94mm) of precipitation is typically accumulated. Throughout the year, there are 125 rainfall days, and 42.4" (1078mm) of precipitation is accumulated.

Ocean temperature

In Portsmouth, New Hampshire, the average seawater temperature is 55.9°F (13.3°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

Daylight

The average length of the day in Portsmouth is 11h.

Sunshine

In Portsmouth, the average sunshine in October is 6h.

UV index

In Portsmouth, the average daily maximum UV index is 3. A UV Index value of 3 to 5 symbolizes a moderate health risk from the exposure to the Sun's UV rays for the ordinary person.
The average daily UV index of 3 transform into the following instructions:
Take precautions - Protection against the skin and eye damage is obliged. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.

What is the temperature in October in Portsmouth?

The average high-temperature, in October, is 59°F (15°C), while the average low-temperature is 41°F (5°C).

How much does it rain in Portsmouth in October?

In Portsmouth, in October, during 9 rainfall days, 3.7" (94mm) of precipitation is typically accumulated.

What is the ocean temperature in October in Portsmouth?

In Portsmouth, New Hampshire, the average seawater temperature in October is 55.9°F (13.3°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

What is the average length of the day in October in Portsmouth?

In October, the average length of the day is 11h.

How long on average sun shines in October in Portsmouth?

In October, the average sunshine in Portsmouth, New Hampshire, is 6h.

What is the UV index reading in October in Portsmouth?

In October, the average daily maximum UV index in Portsmouth, New Hampshire, is 3. A UV Index value of 3 to 5 symbolizes a medium health risk from unsafe exposure to the Sun's UV rays.
Average temperature in October - Portsmouth, NH
  • Average high temperature in October: 59°F

The warmest month (with the highest average high temperature) is July (79°F).
Months with the lowest average high temperature are January and February (32°F).

  • Average low temperature in October: 41°F

The month with the highest average low temperature is July (61°F).
The coldest month (with the lowest average low temperature) is January (16°F).

Average rainfall in October - Portsmouth, NH
  • Average rainfall in October: 3.7"

The wettest month (with the highest rainfall) is November (4.9").
The driest month (with the lowest rainfall) is August (2.8").

Average rainfall days in October - Portsmouth, NH
  • Average rainfall days in October: 9 days

Months with the highest number of rainy days are May and December (12 days).
The month with the lowest number of rainy days is September (8 days).

Average sea temperature in October - Portsmouth, NH
  • Average sea temperature in October: 55.9°F

The best month for swimming (with the highest average sea temperature) is August (65.6°F).
The coldest month (with the lowest average sea temperature) is March (38.5°F).

Average daylight in October / Average sunshine in October - Portsmouth, NH
  • Average daylight in October: 11h

The month with the longest days is June (Average daylight: 15.3h).
The month with shortest days is December (Average daylight: 9.1h).

  • Average sunshine in October: 6h

Months with most sunshine are June, July and August (Average sunshine: 9h).
Months with least sunshine are January, November and December (Average sunshine: 5).

Average UV index in October - Portsmouth, NH
  • Average UV index in October: 3

Months with the highest UV index are June and July (UV index 8).
Months with the lowest UV index are January and December (UV index 1).