When choosing a place to live or move to in New Hampshire, many factors can affect your decision. Each of these factors is unique, but none can have an effect as widespread as the weather. For instance, if your goal is to choose a city with the best weather, how would you find out which one has the best?

Portsmouth has the best weather in New Hampshire; it has 198 sunny days a year, which brings this city the closest to the United States annual average. In addition, the city has higher monthly temperature ranges than other cities in New Hampshire. Also, its Comfort Index ranks it at 6.8, making it one of the most pleasant places in New Hampshire.

Weather patterns are similar in most New Hampshire cities, considering that it is a small state. However, some factors contribute to why Portsmouth has the best weather in the state. Continue reading to learn about Portsmouth’s weather.

Portsmouth Has the Best Weather

As a general rule, most of New Hampshire has similar weather conditions overall, seeing as how the state is only about 9,000 sq. miles in land area. It also has an average elevation of 1,000 feet above sea level; natural land structures can widely influence the region’s weather conditions.

In this case, Portsmouth’s location is of great importance in determining why it has the best weather in the state. It is widely known that large bodies of water, such as an ocean, can impact the landmasses around them.

Portsmouth is on the Atlantic Ocean. Some ways the ocean contributes to Portsmouth weather conditions include:

  • Acts like an absorbing agent, soaking up heat in the summer when it’s available.
  • Stores energy and then releases it in the winter months, thereby creating a comfortable climate that doesn’t fluctuate drastically.
  • Carries the warmth away and to other landmasses, ensuring that excessive heat doesn’t stay trapped in Portsmouth.
  • Creates comfortable “sea-breezes” that assist in moderating temperature spikes and any other weather-related issues.

Generally, landmasses heat up faster than oceans or other large bodies of water do. This means that land temperatures will also quickly raise the air temperatures for that area, contributing to various weather conditions.

Often, coastal cities are more moderate than their continental counterparts. Generally, a coastal winter is warmer than a continental winter, and a seaside summer is cooler than a continental one. This creates a comfortable, desirable place to live and visit.

Ocean Affects Portsmouth’s Weather

Generally, coastal cities have a lot more precipitation than inland cities. This is because water has a unique property that allows it to move freely after absorbing large amounts of heat. Therefore, when ocean water evaporates into the atmosphere, it increases the air temperature and humidity.

This extra moisture and energy generate storms that affect the surrounding area and can also reach areas of great distance away. Therefore, the increased likelihood of rain in Portsmouth is due to the excess humidity and moisture provided by the ocean.

Precipitation Amount in Portsmouth

New Hampshire is well known for its snow days, and they can be wet, frozen, and miserable. Let’s compare Keene, NH, which has similarly pleasant conditions year-round and scores 6.8 on the Comfort Index, to Portsmouth’s averages. For instance, Keene averages around 55 inches of snow a year, several inches over Portsmouth’s average snowfall. For comparison, the United States average is about 28 inches annually.

New Hampshire (NH)  Average rain (inches)Average snow (inches)Precipitation DaysSunny Days
46  68133198
Keene, NH  45.155.4129197
Portsmouth, NH  5053118198

Regional temperatures can also influence weather conditions in the area. In short, the temperature is the amount of heat contained in an object, in this case, the surrounding air. So, for example, as the sun heats up an area, air molecules move faster, raising the temperature.

Portsmouth Best Temperatures

In general, regional temperatures can mean the difference between a sunny, cloudless day or an overcast or rainy day. As the earth heats up during the day, water from various sources, like an ocean or lake, evaporates, creating clouds. As the temperature rises, more moisture evaporates and goes into the air, increasing humidity and cloud cover.

At the same time, differences in air pressure cause fronts to move into the area. This front interacts with moisture and produces wind, storms, and precipitation. Temperature differences create these weather events and further stress why temperature fluctuations make a difference.

Portsmouth, NH    33°36°44°53°64°73°79°76°69°58°49°38°
Keene, NH    31°35°44°58°70°78°83°82°73°61°48°36°

This table shows that Portsmouth still averages better weather conditions than a similar city or the state itself.


New Hampshire is a small state, and its weather conditions are primarily similar throughout. However, cities like Portsmouth will provide better weather patterns due to their proximity to the ocean, which acts as a buffer zone that evens out and moderates daily weather conditions.