Photo: Kenneth C. Zirkel · CC BY-SA 4.0Bethlehem’s winters are colder and snowier than most of the U.S.
A typical July afternoon reaches 86°, a January night drops to 20°, and about 33 inches of snow falls in a normal winter.
A year in Bethlehem at a glance
Each month’s typical high and low, and what it brings.
What stands out about Bethlehem’s climate
Compared with towns across the U.S., with Bethlehem’s place in Pennsylvania beside it.
What a year in Bethlehem feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 184 frost-free days a year
In half of years the last 32° night comes by April 20 and the first by October 24. Frost and day counts come from NOAA’s station at Allentown International Airport, 5 miles from the city’s center point, at about the same height.
The 2023 USDA map puts Bethlehem’s center in zone 7a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 2°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 33 inches of snow a winter
Snow, measured at Allentown International Airport, is heaviest from January through February, about 10 inches a month. Precipitation (rain plus melted snow) adds up to 48 inches a year; July is the wettest month and February the driest. Rain or snow falls on about 129 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Bethlehem
84% of the work is heating. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Allentown International Airport.
Living with Bethlehem’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
184 frost-free days in zone 7a. The last frost comes by Apr 20 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 24.
Months with highs of 62–84° and lows of 40° or more: May, June, August, September and October. 18 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Bethlehem from natural hazards, river flooding is the largest share (64%); heat waves, cold waves, winter storms and ice storms together are 18%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Bethlehem and its neighbors
Every town next door is within a degree of Bethlehem in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Bethlehem’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Bethlehem, PA | 20° | 86° | 48" | 33" |
| Kensington, CT | 19° | 85° | 48" | 39" |
| New Martinsville, WV | 22° | 85° | 46" | 27" |
| Elsmere, KY | 23° | 85° | 47" | 23" |
| Delhi Hills, OH | 23° | 86° | 46" | 23" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Bethlehem averaged 2.2° warmer than the 1900s. The biggest change is in December (+3.9°).
A bigger shift than in 95% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Bethlehem compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Bethlehem’s place among Pennsylvania’s.
Bethlehem weather by month
Highs, lows and precipitation from NOAA’s grid at Bethlehem’s center; snow, wet days and snow on the ground from Allentown International Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 38° | 20° | 3.4" | 9.8" | 11 | 9 | 20° – 37° |
| February | 42° | 22° | 2.7" | 10.8" | 10 | 11 | 20° – 39° |
| March | 50° | 29° | 3.8" | 6.3" | 11 | 6 | 34° – 49° |
| April | 63° | 38° | 3.8" | 0.5" | 12 | 0 | 47° – 56° |
| May | 73° | 49° | 3.9" | 0.0" | 12 | 0 | 56° – 66° |
| June | 81° | 58° | 4.4" | 0.0" | 11 | 0 | 67° – 72° |
| July | 86° | 63° | 5.0" | 0.0" | 11 | 0 | 70° – 78° |
| August | 84° | 61° | 4.7" | 0.0" | 10 | 0 | 68° – 76° |
| September | 77° | 54° | 4.7" | 0.0" | 10 | 0 | 62° – 69° |
| October | 65° | 42° | 4.4" | 0.2" | 10 | 0 | 48° – 61° |
| November | 54° | 33° | 3.3" | 0.9" | 9 | 1 | 38° – 48° |
| December | 43° | 26° | 4.0" | 4.6" | 12 | 5 | 26° – 46° |
| Year | 63° | 41° | 48.1" | 33.1" | 129 | 31 |
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 26° to 46°. June is the most reliable, staying within 6°.
Where Bethlehem’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Bethlehem’s center.
- Snow: Allentown International Airport.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Allentown International Airport, 5 miles from the city’s center point, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Bethlehem’s climate
What is the weather like in Bethlehem?
A typical July afternoon reaches 86°, a January night drops to 20°, and about 33 inches of snow falls in a normal winter. Colder January nights than 58% of U.S. towns; hotter July afternoons than 57% of U.S. towns.
How cold does it get in Bethlehem in winter?
January nights average 20°. About 118 nights a year reach 32° or below and 1 reach 0° or below. In the coldest January of the last 30 years the month averaged 20°.
How much snow does Bethlehem get?
About 33 inches in a normal winter at Allentown International Airport, heaviest from January through February, about 10 inches a month, with snow on the ground about 31 days a year.
How hot does it get in Bethlehem?
July, with a typical high of 86° and a low of 63°. About 18 days a year reach 90° (Allentown International Airport).
When is the first and last frost in Bethlehem?
In half of years the last spring frost (32°) comes by April 20 and the first fall frost by October 24, about 184 frost-free days, at Allentown International Airport.
What growing zone is Bethlehem in?
Zone 7a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 2°.
What is the best time of year to visit Bethlehem?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Bethlehem getting warmer?
Yes: 1991–2020 averaged 2.2° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 95% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Bethlehem.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.