Bethlehem, New Hampshire climate: Normal weather by month, frost dates and records
Bethlehem's normal year runs from 3°F January nights to 80°F July afternoons, with 41.0 inches of precipitation and 101 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 5.6°C, January lows of −16°C, July highs of 27°C, 1,041 mm of precipitation a year.
- NOAA stationBethlehem 2
- Station IDUSC00270706
- Location44.31°N 71.66°W
- Elevation1,180 ft (360 m)
- Population (town)2,554
- Census place1,097
On October 22, the normal high in Bethlehem is 56°F and the normal low 31°F, and the chance of measurable rain or snow is 45%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Bethlehem.
- Jan 28° 3°
- Feb 30° 4°
- Mar 40° 14°
- Apr 53° 27°
- May 67° 39°
- Jun 76° 48°
- Jul 80° 53°
- Aug 79° 50°
- Sep 72° 42°
- Oct 58° 32°
- Nov 45° 24°
- Dec 33° 12°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Bethlehem each month?
July is the warmest month, with normal highs of 80°F; January the coldest, with normal lows of 3°F. The most precipitation falls in July (4.63 in), the least in February (2.04 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 28°F | 3°F | 15.6°F | 2.59 | 21.3 | 16 | <1 | 31 | 9 h 10 min |
| February | 30°F | 4°F | 17.3°F | 2.04 | 21.5 | 12 | <1 | 28 | 10 h 30 min |
| March | 40°F | 14°F | 27.1°F | 2.56 | 16.7 | 14 | <1 | 29 | 11 h 50 min |
| April | 53°F | 27°F | 40.4°F | 3.15 | 5.4 | 13 | <1 | 21 | 13 h 20 min |
| May | 67°F | 39°F | 53.2°F | 3.69 | 0.4 | 16 | <1 | 7 | 14 h 40 min |
| June | 76°F | 48°F | 61.8°F | 4.24 | 0.0 | 17 | 1 | <1 | 15 h 30 min |
| July | 80°F | 53°F | 66.4°F | 4.63 | 0.0 | 15 | 1 | <1 | 15 h 10 min |
| August | 79°F | 50°F | 64.5°F | 4.16 | 0.0 | 13 | 1 | <1 | 14 h 10 min |
| September | 72°F | 42°F | 56.8°F | 3.58 | 0.0 | 11 | <1 | 5 | 12 h 40 min |
| October | 58°F | 32°F | 45.3°F | 3.97 | 1.6 | 14 | <1 | 16 | 11 h |
| November | 45°F | 24°F | 34.1°F | 3.04 | 7.1 | 14 | <1 | 25 | 9 h 40 min |
| December | 33°F | 12°F | 22.3°F | 3.34 | 26.9 | 16 | <1 | 30 | 8 h 50 min |
| Year (annual) | 55°F | 29°F | 42.1°F | 40.99 | 100.9 | 169 | 3 | 191 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −2°C | −16°C | −9.1°C | 66 mm | 54 cm |
| February | −1°C | −15°C | −8.2°C | 52 mm | 55 cm |
| March | 4°C | −10°C | −2.7°C | 65 mm | 42 cm |
| April | 12°C | −3°C | 4.7°C | 80 mm | 14 cm |
| May | 20°C | 4°C | 11.8°C | 94 mm | 1 cm |
| June | 24°C | 9°C | 16.6°C | 108 mm | 0 cm |
| July | 27°C | 12°C | 19.1°C | 118 mm | 0 cm |
| August | 26°C | 10°C | 18.1°C | 106 mm | 0 cm |
| September | 22°C | 6°C | 13.8°C | 91 mm | 0 cm |
| October | 15°C | 0°C | 7.4°C | 101 mm | 4 cm |
| November | 7°C | −5°C | 1.2°C | 77 mm | 18 cm |
| December | 1°C | −11°C | −5.4°C | 85 mm | 68 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00270706; 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.
When is the best weather to visit Bethlehem?
Normal highs sit between 65°F and 85°F in May, 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 USC00270706.
When is the last frost in Bethlehem?
In Bethlehem, the last spring frost (32°F) comes after May 24 in half of years and after June 8 in one year in ten; the first autumn frost comes before September 18 in half of years and before September 6 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 241 year in 10 after June 8; 9 in 10 after May 6
- First autumn frost, half of years before
- September 181 year in 10 before September 6; 9 in 10 before October 1
NOAA puts the median frost-free season at 116 days, and the season without a hard freeze (28°F) at 142 days.
A hard freeze (28°F) comes after May 7 in half of springs and before September 30 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Bethlehem in zone 5a in ZIP code 03574, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Bethlehem's NOAA station is in zone 4b: the coldest night of a typical year reaches −21°F (18 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in New Hampshire · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00270706; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. 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 in Bethlehem?
In a normal year in Bethlehem, 3 days a year reach 90°F, 191 nights fall to 32°F or colder and 169 days bring measurable precipitation.
- Days at 90°F or more
- 3a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 191a normal year
- Days that stay below freezing
- 69high of 32°F or less
- Days with 0.01 inch of precipitation
- 169a normal year
- Days with 1 inch of snow or more
- 30a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00270706.
How sunny is Bethlehem?
Over a year 66% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Bethlehem, 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 much heating and cooling does Bethlehem need?
A normal year in Bethlehem brings 8,548 heating degree days, 59% more than the median U.S. place (5,373), and 227 cooling degree days, 75% 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 1,780 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,531 | 0 |
| February | 1,337 | 0 |
| March | 1,176 | 0 |
| April | 740 | 1 |
| May | 374 | 8 |
| June | 138 | 42 |
| July | 49 | 94 |
| August | 80 | 64 |
| September | 262 | 17 |
| October | 611 | 1 |
| November | 927 | 0 |
| December | 1,322 | 0 |
| Year (annual) | 8,548 | 227 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00270706. 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.
How does Bethlehem's climate compare?
Bethlehem is warmer than 3 of the other 27 places with their own NOAA record in New Hampshire, and wetter than 6. Across the 7,247 U.S. stations with normals, its annual mean of 42.1°F is warmer than 10%.
In the Köppen classification computed from these normals, Bethlehem 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.
Which places near Bethlehem share this climate record?
2 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Concord, VT1,149 people · 14 mi NW
- Gilman, VT146 people · 8 mi N
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Bethlehem's climate
What is the coldest month in Bethlehem?
January, with a normal high of 28°F and a normal low of 3°F. The warmest is July (80°F by day, 53°F at night).
Does it snow in Bethlehem?
Yes: 101 inches in a normal year, falling on 51 days with 0.1 inch or more, the most in December (26.9 inches).
What is the rainiest month in Bethlehem?
July, with 4.63 in of precipitation in a normal year; the driest is February with 2.04 in.
What plant hardiness zone is Bethlehem in?
The USDA's 2023 map puts Bethlehem in zone 5a in ZIP code 03574, the nearest ZIP area. By the same method at Bethlehem's NOAA station, the coldest night of a typical year reaches −21°F (18 years, 1991-2020): zone 4b.
How late can frost come in Bethlehem?
In half of years the last 32°F night comes after May 24; in one year in ten it comes after June 8. Waiting until June 8 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, NH7 miles from this station, 42.5°F a year
- Jefferson, NH11 miles from this station, 42.5°F a year
- Lancaster, NH14 miles from this station, 41.9°F a year
- Mount Washington, NH18 miles from this station, 28.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made