Currently, February is the cheapest month in which you can book a flight from San Francisco to Portsmouth, New Hampshire (average of $89). Flying from San Francisco to Portsmouth, New Hampshire in December is currently the most expensive (average of $173). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
In terms of precipitation, rainfall in Portsmouth, New Hampshire ranges from 2.2 - 5.1 inches per month. November is typically the wettest month, when rainfall can reach 5.1 in. August is typically the driest time to visit Portsmouth, New Hampshire when rainfall is around 2.2 in.
If weather is an important factor for your trip to Portsmouth, New Hampshire, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 69.8 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 24.8 F).