Merrimack in Winter
In winter (December, January and February), Merrimack sees average daytime highs around 36°F and overnight lows near 21°F, with 10.2 in of precipitation over about 28 wet days across the season. It is the coldest season of the year and the driest season of the year.
Across winter, daytime highs hold fairly steady around 36°F. The sky is clear or mostly clear about 33% of the time across winter, and the air most often feels dry.
Winter is Merrimack's weakest season of the year to visit on our travel score. For the whole year in context, see Merrimack's year-round climate.
- Avg daytime high
- 36°F
- coldest season of the year
- Avg overnight low
- 21°F
- Precipitation
- 10.2 in
- 28 wet days
- Avg wind
- 8 mph
- Travel score
- 0.0
- weakest season of the year
- Months
- Dec · Jan · Feb
Temperature in Merrimack in Winter
Across winter, daytime highs hold fairly steady around 36°F.
A typical winter day in Merrimack reaches about 36°F and drops to 21°F overnight. The warmest of the three months is December, the coolest January.
How winter really feels in Merrimack
Once humidity and wind are folded in, winter brings about 0 days that feel above 90°F and 90 that feel at or below 32°F.
The story in winter is cold — wind chill drags the overnight "feels like" below the raw low.
Merrimack weather by month
How the three winter months (December, January and February) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 34° / 19° | 3.1 | 9.6 | 6.7 | 9.2 | 0.0 |
| Feb | 36° / 20° | 3.0 | 8.4 | 6 | 10.2 | 0.0 |
| Mar | 44° / 28° | 4.1 | 10.9 | 5.4 | 11.6 | 0.8 |
| Apr | 57° / 39° | 3.7 | 10.5 | 1.5 | 13.1 | 3.8 |
| May | 67° / 48° | 3.2 | 10.8 | 0 | 14.4 | 6.0 |
| Jun | 77° / 58° | 3.5 | 10.8 | 0 | 15.1 | 6.5 |
| Jul | 82° / 64° | 3.4 | 10.3 | 0 | 14.8 | 6.0 |
| Aug | 80° / 62° | 3.4 | 9.6 | 0 | 13.7 | 6.6 |
| Sep | 73° / 54° | 3.4 | 8 | 0 | 12.3 | 7.0 |
| Oct | 61° / 44° | 3.8 | 9.3 | 0.3 | 10.8 | 5.1 |
| Nov | 49° / 34° | 3.4 | 9.4 | 1.4 | 9.5 | 2.0 |
| Dec | 39° / 25° | 4.1 | 10.3 | 5.5 | 8.9 | 0.1 |
Cloud cover in Winter
The sky is clear or mostly clear about 33% of the time across winter.
Chance of precipitation in Winter
Merrimack gets around 10.2 in of rain and snow over 28 wet days across winter. The line is the day-by-day chance of measurable precipitation.
Humidity in Winter
Most of winter feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Winter
Winds average 8 mph across winter.
Sunrise & sunset in Winter
Daylight runs from about 9 h 06 min in early December to 10 h 54 min by late February. The lit band spans sunrise to sunset each day.
Solar energy in Winter
Average shortwave solar energy reaching the ground each day across winter, about 2.1 kWh/m².
Hazard calendar for Merrimack
None of Merrimack's seasonal hazards peak in winter. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do.
Merrimack sits in the Atlantic hurricane belt; the season peaks August–October.
Is winter a good time to visit Merrimack?
Our two travel scores rate winter for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
winter is a weaker month for outdoor sightseeing in Merrimack.
What to pack for Merrimack in Winter
From winter's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In winter, Merrimack sees daytime highs around 36°F and nights near 21°F. Pack a warm layer and a heavy coat. Worth having: rain gear. About 28 days see rain.
UV index in Merrimack in Winter
Clear-sky midday UV across winter averages around 2. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Merrimack peaks around July 10 at about 7 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 23 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 3 | 4 | 5 | 7 | 7 | 7 | 5 | 6 | 3 | 2 | 1 |
| Level | Low | Moderate | Moderate | High | Very high | High | Very high | Moderate | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 3 | Moderate |
| Mar | 4 | Moderate |
| Apr | 5 | High |
| May | 7 | Very high |
| Jun | 7 | High |
| Jul | 7 | Very high |
| Aug | 5 | Moderate |
| Sep | 6 | High |
| Oct | 3 | Moderate |
| Nov | 2 | Moderate |
| Dec | 1 | Low |
Air quality in Merrimack in Winter
Average fine-particle pollution (PM2.5) through the year — so you can see where winter falls, not just the annual average.
Air quality in Merrimack is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (November, 8 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 9 | 13 | 13 | 13 | 14 | 13 | 16 | 14 | 11 | 9 | 8 | 9 |
| Level | Good | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 9 | Good |
| Feb | 13 | Moderate |
| Mar | 13 | Moderate |
| Apr | 13 | Moderate |
| May | 14 | Moderate |
| Jun | 13 | Moderate |
| Jul | 16 | Moderate |
| Aug | 14 | Moderate |
| Sep | 11 | Good |
| Oct | 9 | Good |
| Nov | 8 | Good |
| Dec | 9 | Good |
Where is Merrimack?
Merrimack sits at 42.9°N, 71.5°W, 154 ft above sea level, in United States. The nearest listed city is Bedford, 5.6 mi away.
Topography around Merrimack
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Merrimack.
Within 2 miles, the terrain around Merrimack has only modest variations in elevation — a maximum elevation change of 289 ft around an average of 203 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,227 ft; within 50 miles, large variations in elevation — a maximum elevation change of 3,176 ft.
The land around Merrimack is covered by trees (73%) within 2 miles, trees (77%) within 10 miles, and trees (82%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Merrimack (42.8651°, -71.4934°, elevation 154 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.