Merrimack (NH) Temperature by Month
Merrimack in New Hampshire, United States of America sees significant seasonal temperature differences, with daytime highs between 1°C (34°F) in January and 29°C (84°F) in July, averaging 15°C (59°F) annually. Explore the full monthly breakdown below.
Merrimack Monthly Temperatures
The climate in Merrimack is known for significant temperature differences throughout the year. At night, this contrast is just as clear, with lows ranging from 17°C (63°F) in July to -9°C (16°F) in January.
The chart below illustrates the average maximum day and minimum night temperatures in Merrimack by month:
The minimum temperature is often recorded between 4 AM and 6 AM, while the highest temperature is usually reached at 3 PM, when the sun's heating effect is strongest. July, the warmest month, gets 295 hours of sunshine.
The chart below shows the average temperature throughout the year:
Temperature: Merrimack vs the United States of America
The map below shows the annual temperature across the United States of America. You can also select individual months if you want to compare a specific time of year.
very warm
warm
pleasant
moderate
cold
very cold
Merrimack vs World: Temperature Compared
Merrimack's average annual maximum temperature is 15°C (59°F). To put that in context, here's how it compares to a few well-known destinations:
Athens, Greece sits at 23°C (73°F) on average, with hot dry summers and mild winters characteristic of the Mediterranean.
Reykjavík, Iceland averages 9°C (48°F) a year — mild summers by Icelandic standards, but cold winters and frequent wind.
Boston, USA averages 16°C (61°F) annually, with four distinct seasons and cold winters that rival northern Europe.
Tokyo, Japan averages 21°C (70°F) a year, with hot summers, cool winters, and a well-defined cherry blossom spring.
What Does the Temperature Feel Like in Merrimack?
Temperature alone doesn't tell the whole story — humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.
In the cooler months, when temperatures drop below 10°C, high humidity makes the cold feel more cutting than it would in dry conditions.
In Merrimack, January is the coolest month, with average highs of 1°C (34°F) and humidity around 67% — considered high. In July, the warmest month, temperatures average 29°C (84°F) with 72% humidity — conditions that feel high. For a full picture, see our humidity page.
Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.
The readings come from a range of sources — land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.
For cities and regions with significant elevation, altitude is one of the biggest factors shaping local temperatures. As a rule of thumb, temperatures fall by around 6°C for every 1,000 metres gained — so a city at 2,000 metres will typically be around 12°C cooler than a city at sea level in the same region. Higher ground also tends to see more dramatic day-to-night temperature swings, since thinner air loses heat faster after sunset.
For more on Merrimack's weather — including monthly rainfall, sunshine hours, and humidity — visit our Merrimack climate page.
