Jefferson, New Hampshire climate: Climate normals at a NOAA weather station
Jefferson's normal year runs from 7°F January nights to 78°F July afternoons, with 41.0 inches of precipitation and 95 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 5.8°C, January lows of −14°C, July highs of 25°C, 1,042 mm of precipitation a year.
- NOAA stationJefferson
- Station IDUSC00274329
- Location44.42°N 71.50°W
- Elevation1,235 ft (376 m)
On October 23, the normal high in Jefferson is 52°F and the normal low 35°F, and the chance of measurable rain or snow is 47%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Jefferson.
- Jan 26° 7°
- Feb 29° 9°
- Mar 38° 18°
- Apr 51° 30°
- May 64° 42°
- Jun 73° 51°
- Jul 78° 56°
- Aug 76° 54°
- Sep 67° 45°
- Oct 55° 37°
- Nov 42° 27°
- Dec 31° 16°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Jefferson each month?
July is the warmest month, with normal highs of 78°F; January the coldest, with normal lows of 7°F. The most precipitation falls in June (4.40 in), the least in February (2.28 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 26°F | 7°F | 16.8°F | 2.51 | 20.1 | 16 | <1 | 31 | 9 h 10 min |
| February | 29°F | 9°F | 19.0°F | 2.28 | 19.8 | 14 | <1 | 28 | 10 h 30 min |
| March | 38°F | 18°F | 27.6°F | 2.61 | 16.7 | 14 | <1 | 29 | 11 h 50 min |
| April | 51°F | 30°F | 40.6°F | 3.36 | 6.5 | 14 | <1 | 19 | 13 h 20 min |
| May | 64°F | 42°F | 53.1°F | 3.80 | 0.5 | 15 | <1 | 3 | 14 h 50 min |
| June | 73°F | 51°F | 61.6°F | 4.40 | 0.0 | 15 | 1 | <1 | 15 h 30 min |
| July | 78°F | 56°F | 66.7°F | 4.26 | 0.0 | 13 | 1 | <1 | 15 h 10 min |
| August | 76°F | 54°F | 64.8°F | 3.98 | 0.0 | 12 | <1 | <1 | 14 h 10 min |
| September | 67°F | 45°F | 56.4°F | 3.34 | 0.0 | 11 | <1 | 2 | 12 h 40 min |
| October | 55°F | 37°F | 46.0°F | 4.29 | 1.8 | 14 | <1 | 9 | 11 h |
| November | 42°F | 27°F | 34.0°F | 2.95 | 7.7 | 15 | <1 | 24 | 9 h 40 min |
| December | 31°F | 16°F | 23.3°F | 3.26 | 21.7 | 17 | <1 | 29 | 8 h 50 min |
| Year (annual) | 52°F | 33°F | 42.5°F | 41.04 | 94.8 | 168 | 2 | 173 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −3°C | −14°C | −8.4°C | 64 mm | 51 cm |
| February | −2°C | −13°C | −7.2°C | 58 mm | 50 cm |
| March | 3°C | −8°C | −2.4°C | 66 mm | 42 cm |
| April | 11°C | −1°C | 4.8°C | 85 mm | 17 cm |
| May | 18°C | 5°C | 11.7°C | 97 mm | 1 cm |
| June | 23°C | 10°C | 16.4°C | 112 mm | 0 cm |
| July | 25°C | 13°C | 19.3°C | 108 mm | 0 cm |
| August | 24°C | 12°C | 18.2°C | 101 mm | 0 cm |
| September | 20°C | 7°C | 13.6°C | 85 mm | 0 cm |
| October | 13°C | 3°C | 7.8°C | 109 mm | 5 cm |
| November | 5°C | −3°C | 1.1°C | 75 mm | 20 cm |
| December | −1°C | −9°C | −4.8°C | 83 mm | 55 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00274329; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Jefferson?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, September has the fewest days with rain (11).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00274329.
When is the last frost at Jefferson?
In Jefferson, the last spring frost (32°F) comes after May 8 in half of years and after May 23 in one year in ten; the first autumn frost comes before October 1 in half of years and before September 16 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 81 year in 10 after May 23; 9 in 10 after April 27
- First autumn frost, half of years before
- October 11 year in 10 before September 16; 9 in 10 before October 17
NOAA puts the median frost-free season at 146 days, and the season without a hard freeze (28°F) at 172 days.
A hard freeze (28°F) comes after April 27 in half of springs and before October 16 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Jefferson in zone 4b in ZIP code 03583, the nearest ZIP area.
Frost dates for every NOAA station in New Hampshire · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00274329; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Jefferson?
In a normal year in Jefferson, 2 days a year reach 90°F, 173 nights fall to 32°F or colder and 168 days bring measurable precipitation.
- Days at 90°F or more
- 2a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 173a normal year
- Days that stay below freezing
- 74high of 32°F or less
- Days with 0.01 inch of precipitation
- 168a normal year
- Days with 1 inch of snow or more
- 28a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00274329.
How sunny is it at Jefferson?
Over a year 66% of the sunlight that would reach the ground under clear skies gets through the clouds at Jefferson, 3.5 kWh per square metre a day. September is the sunniest month (73%) and December the cloudiest (54%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 59% | 1.4 |
| February | 62% | 2.3 |
| March | 65% | 3.5 |
| April | 64% | 4.4 |
| May | 64% | 5.1 |
| June | 67% | 5.5 |
| July | 71% | 5.6 |
| August | 73% | 5.0 |
| September | 73% | 4.0 |
| October | 62% | 2.4 |
| November | 59% | 1.6 |
| December | 54% | 1.1 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Jefferson record?
A normal year at Jefferson brings 8,391 heating degree days, 56% more than the median U.S. place (5,373), and 219 cooling degree days, 76% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,797 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,494 | 0 |
| February | 1,289 | 0 |
| March | 1,158 | 0 |
| April | 733 | 1 |
| May | 377 | 7 |
| June | 142 | 38 |
| July | 41 | 94 |
| August | 69 | 60 |
| September | 276 | 18 |
| October | 590 | 1 |
| November | 930 | 0 |
| December | 1,293 | 0 |
| Year (annual) | 8,391 | 219 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00274329. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Have recent years at Jefferson been warmer than normal?
2025 averaged 42.2°F, 0.3°F below the 1991-2020 normal of 42.5°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 43.5°F | +1.0°F | 38.36 | 84.0 |
| 2022 | 42.8°F | +0.3°F | 41.17 | 72.3 |
| 2023 | 44.1°F | +1.6°F | 47.45 | 75.4 |
| 2024 | 44.6°F | +2.1°F | 50.49 | 111.8 |
| 2025 | 42.2°F | −0.3°F | 37.23 | – |
Source: observed years: ACIS, station USC00274329. A year counts only with all twelve months complete.
How does Jefferson's climate compare?
Jefferson is warmer than 4 of the 28 places with their own NOAA record in New Hampshire, and wetter than 7. Across the 7,247 U.S. stations with normals, its annual mean of 42.5°F is warmer than 11%.
In the Köppen classification computed from these normals, Jefferson is Dfb: continental, no dry season, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Questions about Jefferson's climate
What is the coldest month at Jefferson?
January, with a normal high of 26°F and a normal low of 7°F. The warmest is July (78°F by day, 56°F at night).
Does it snow at Jefferson?
Yes: 95 inches in a normal year, falling on 67 days with 0.1 inch or more, the most in December (21.7 inches).
What is the rainiest month at Jefferson?
June, with 4.40 in of precipitation in a normal year; the driest is February with 2.28 in.
What plant hardiness zone is Jefferson in?
The USDA's 2023 map puts Jefferson in zone 4b in ZIP code 03583, the nearest ZIP area.
How late can frost come at Jefferson?
In half of years the last 32°F night comes after May 8; in one year in ten it comes after May 23. Waiting until May 23 leaves about a one-in-ten chance of a later frost.
Nearby and next
- New Hampshire climateThe statewide normals and every place in the state
- Whitefield, NH4 miles from this station, 42.5°F a year
- Lancaster, NH7 miles from this station, 41.9°F a year
- York Pond, NH11 miles from this station, 40.4°F a year
- Bethlehem, NH11 miles from this station, 42.1°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made