Portsmouth, IA has a humid continental climate. This means summers are hot and humid with temperatures averaging in the high 80s, while winters are cool to cold with temperatures staying between the mid 20s and high 30s. Precipitation is spread evenly throughout the year with an average of 36 inches annually. Snowfall can be variable though it typically falls between five and six inches per season.
Portsmouth, Iowa gets 34 inches of rain, on average, per year. The US average is 38 inches of rain per year.
Portsmouth averages 30 inches of snow per year. The US average is 28 inches of snow per year.
On average, there are 219 sunny days per year in Portsmouth. The US average is 205 sunny days.
Portsmouth gets some kind of precipitation, on average, 95 days per year. Precipitation is rain, snow, sleet, or hail that falls to the ground. In order for precipitation to be counted you have to get at least .01 inches on the ground to measure.
Weather Highlights
Summer High: the July high is around 85 degrees
Winter Low: the January low is 11
Rain: averages 34 inches of rain a year
Snow: averages 30 inches of snow a year