2025 Compare Climate & Weather:
Old Greenwich, CT vs Portsmouth, NH

Highlights

On average, there are 198 sunny days per year in Portsmouth. Old Greenwich averages 175 sunny days per year. The US average is 205 sunny days.

Portsmouth, New Hampshire gets 50.1 inches of rain, on average, per year. Old Greenwich, Connecticut gets 50.7 inches of rain, on average, per year. The US average is 38.1 inches of rain per year.

Portsmouth averages 53.2 inches of snow per year. Old Greenwich averages 29.8 inches of snow per year. The US average is 27.8 inches of snow per year.

Weather Highlights

Portsmouth, New Hampshire
Summer High: the July high is around 81.9 degrees
Winter Low: the January low is 13.8
Rain: averages 50.1 inches of rain a year
Snow: averages 53.2 inches of snow a year

Old Greenwich, Connecticut
Summer High: the July high is around 83.2 degrees
Winter Low: the January low is 21.6
Rain: averages 50.7 inches of rain a year
Snow: averages 29.8 inches of snow a year

BestPlaces Comfort Index

The annual BestPlaces Comfort Index for Portsmouth is 6.8 (10=best), which means it is one of the most pleasant places in New Hampshire.

The annual BestPlaces Comfort Index for Old Greenwich is 7.1 (10=best), which means it is more comfortable than most places in Connecticut.

Today's Weather - Old Greenwich, CT

60°F

Today's Weather - Portsmouth, NH

52°F

Average Monthly High / Low (°F)

Hot, Freezing, Rainy, Snowy Days: Old Greenwich / Portsmouth

July is the hottest month for Old Greenwich with an average high temperature of 83.2°, which ranks it as about average compared to other places in Connecticut. In Old Greenwich, there are 5 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Old Greenwich are June, August and September.

July is the hottest month for Portsmouth with an average high temperature of 81.9°, which ranks it as warmer than most places in New Hampshire. In Portsmouth, there are 4 comfortable months with high temperatures in the range of 70-85°. The most pleasant months of the year for Portsmouth are June, August and July.

January has the coldest nighttime temperatures for Old Greenwich with an average of 21.6°. This is warmer than most places in Connecticut.

January has the coldest nighttime temperatures for Portsmouth with an average of 13.8°. This is one of the warmest places in New Hampshire.

In Old Greenwich, there are 8.5 days annually when the high temperature is over 90°, which is hotter than most places in Connecticut.

In Portsmouth, there are 8.0 days annually when the high temperature is over 90°, which is hotter than most places in New Hampshire.

In Old Greenwich, there are 106.1 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in Connecticut.

In Portsmouth, there are 149.8 days annually when the nighttime low temperature falls below freezing, which is warmer than most places in New Hampshire.

In Old Greenwich, there are 0.9 days annually when the nighttime low temperature falls below zero°, which is warmer than most places in Connecticut.

In Portsmouth, there are 7.2 days annually when the nighttime low temperature falls below zero°, which is warmer than most places in New Hampshire.

September is the wettest month in Old Greenwich with 4.7 inches of rain, and the driest month is February with 3.1 inches. The wettest season is Winter with 27% of yearly precipitation and 22% occurs in Spring, which is the driest season. The annual rainfall of 50.7 inches in Old Greenwich means that it is wetter than most places in Connecticut.


November is the wettest month in Portsmouth with 4.8 inches of rain, and the driest month is January with 3.5 inches. The wettest season is Summer with 28% of yearly precipitation and 23% occurs in Spring, which is the driest season. The annual rainfall of 50.1 inches in Portsmouth means that it is one of the wettest places in New Hampshire.

May is the rainiest month in Old Greenwich with 12.0 days of rain, and February is the driest month with only 9.0 rainy days. There are 123.9 rainy days annually in Old Greenwich, which is rainier than most places in Connecticut. The rainiest season is Summer when it rains 28% of the time and the driest is Winter with only a 24% chance of a rainy day.

May is the rainiest month in Portsmouth with 11.4 days of rain, and February is the driest month with only 7.7 rainy days. There are 118.3 rainy days annually in Portsmouth, which is one of the least rainy places in New Hampshire. The rainiest season is Summer when it rains 27% of the time and the driest is Spring with only a 23% chance of a rainy day.

An annual snowfall of 29.8 inches in Old Greenwich means that it is less snowy than most places in Connecticut.

An annual snowfall of 53.2 inches in Portsmouth means that it is one of the least snowy places in New Hampshire.

February is the snowiest month in Old Greenwich with 9.0 inches of snow, and 6 months of the year have significant snowfall.

January is the snowiest month in Portsmouth with 16.7 inches of snow, and 6 months of the year have significant snowfall.