Climate and monthly weather forecastBethlehem, PA
Climate and monthly weather forecast
The climate of Bethlehem
Bethlehem in Pennsylvania, USA, experiences a humid continental climate - a condition recognized by the Köppen climate classification as Dfa. This condition characterizes the city with no dry season and hot summer temperatures. Observing the given climatological data, the temperature fluctuates from a minimum of 21.6°F (-5.8°C) in January to a maximum of 83.5°F (28.6°C) in July.The average relative humidity hovers around 76% to 82% throughout the year. Rainfall spans from a low of 1.57" (40mm) in September to a high of 2.91" (74mm) in July, with rainfall occurrences ranging from 7.8 to 17.8 days monthly. While January experiences significant snowfall at 3.23" (82mm) over 7.8 days, the snow ceases from June to September. September proudly boasts the longest daylight hours at 15.0 hours and the most sunshine hours at 10.4. The highest ultraviolet index is recorded from May through July, while pressure, visibility, wind speeds, and cloud cover percentages consistently shift within marginal ranges throughout the year.
The unique climatic tilts of Bethlehem are observed in the absence of snow from June to September and the radiant sunshine of July over 11.8 days on average. July also stands out as the month with the most rainfall.
The best time to visit Bethlehem
For outdoor enthusiasts, the best time to visit Bethlehem falls between May and September. These months offer longer daylight hours ranging from 14.5 to 15 hours and abundant sunshine totaling 8.3 to 10.4 hours a day. Temperatures during these months are also ideal for outdoor activities, as they range from 69.6°F (20.9°C) to 83.5°F (28.6°C).The worst time to visit Bethlehem
From a visitor's perspective, the colder months of December through February may be the least appealing time to visit Bethlehem. During these months, the city experiences lower temperatures, dipping to a chilly 21.6°F (-5.8°C) in January. Additionally, the winter period sees shorter daylight hours, ranging from 9.3 to 10.7 hours, impacting outdoor activities' planning and duration.Spring weather in Bethlehem
With a captivating blend of mild temperatures and blooming flora, spring in Bethlehem begins in March and lasts till May. The temperatures during this period rise consistently from 46°F (7.8°C) in March to a pleasant 69.6°F (20.9°C) in May.Summer weather in Bethlehem
Bethlehem's summer, from June through August, welcomes the warmest conditions of the year. The mercury seldom drops below 77.4°F (25.2°C) in June and can climb up to 83.5°F (28.6°C) in July. August remains relatively cooler, with temperatures sparingly falling to 81°F (27.2°C). The city enjoys a high average daylight duration, basking under the sun for a gratifying 14.7 to 15 hours.Autumn weather in Bethlehem
Bethlehem warmly welcomes autumn from September, offering a pleasant climate as temperatures cool off from the high of summer. Although the season starts off with a balmy 74.3°F (23.5°C) in September, temperatures drop steadily till they reach 50°F (10°C) in November.Winter weather in Bethlehem
Winter in Bethlehem is marked by cold, freezing temperatures and an increased possibility of snowfall. The city experiences temperatures that average from 34°F (1.1°C) in December to 21.6°F (-5.8°C) in January - the coldest month of the year. Snow becomes a frequent sight, with January boasting the highest snowfall at 3.23" (82mm) over 7.8 days on average.Weather in January
Moving into January, Bethlehem, Pennsylvania experiences a colder turn in temperatures that provide a fresh chill in the air. January's weather falls on the severe end of the winter scale, with quite high relative humidity percentages at 78% and snowfall inches peaking at 3.23" (82mm). Weather in January »Weather in February
As the second month of the year rolls into Bethlehem, there is a continuation of January's frosty weather influence. Despite the mounting temperatures, which range up to 37.8°F (3.2°C) from 21.6°F (-5.8°C), February resonates strongly with its predecessor in terms of inclement weather. Weather in February »Weather in March
Bethlehem city embarks on a transitional journey from depths of wintertime to stirrings of spring during March. As winter recedes, a milder weather pattern unfolds where the temperature extends up to 46°F (7.8°C), and snowfall reduces significantly to 4.13" (105mm). Weather in March »Weather in April
As April arrives, Bethlehem shakes off the last dregs of winter, as the citywide temperature comfortably resides between 30°F (-1.1°C) to 58.6°F (14.8°C). Human and nature activity bursts into life after the lengthy dormant period. Weather in April »Weather in May
May rolls in and Bethlehem is bathed in the warm embrace of spring. The Bethlehem weather in May is punctuated with a high temperature that soars to 69.6°F (20.9°C), initiating a real departure from the previous months. With this change, Bethlehem experiences a considerable increase in daylight hours and diminished snowfall days effectively to none. Weather in May »Weather in June
By June, Bethlehem revels in the full swing of summer, accompanied by a consistent change in the weather pattern. The temperature inches up to 77.4°F (25.2°C), echoing the intensity of the summer season across the region. Days are lengthier, and there is a considerable spike in sunshine hours which cap at 15 per day. Weather in June »Weather in July
Unfolding amidst the summer revelry is July, which stakes its claim as the hottest month in Bethlehem with peaks touching 83.5°F (28.6°C). As temperatures notably amplify, pressure slightly takes a dip, signifying the general stability attached to summer's full bloom. Weather in July »Weather in August
August in Bethlehem still falls within the city's hot season, even with a slight decline in the temperature to 81°F (27.2°C). Compared to July, this period brings forth subtle hints of approaching autumn. Regardless, sunshine hours retain their extension, almost kissing the 14-hour mark, availing longer daylight for outdoor pursuits. Weather in August »Weather in September
September arrives in Bethlehem softly ushering in the gentle fall season. Bethlehem enjoys a slight dip in temperature in September, resting comfortably at 74.3°F (23.5°C). Although rainfall inches reduce to 1.57" (40mm), the number of rainy days increases, hinting at shorter bursts of precipitation. Weather in September »Weather in October
In October, Bethlehem witnesses another remarkable shift in the weather where the temperature drops to a high of 62.1°F (16.7°C). Wind speed gathers momentum slightly, ushering in cooler, crisper air. The dwindling daylight hours and minimal sunshine contribute substantially to the colder weather. Weather in October »Weather in November
As November rolls into Bethlehem, the city's weather takes another turn, this time towards the chillier confines of early winter with the high temperature dropping to 50°F (10°C). Snowfall resurfaces with 0.28" (7mm) recorded, offering the first taste of the coming winter season. Weather in November »Weather in December
December in Bethlehem indicates the deep plunge into winter, characterized by the mercury's descent to 40.1°F (4.5°C). One of the most prominent instances of cold weather, December boasts of the highest snowfall inches in the second half of the calendar year, falling at 2.48" (63mm). Weather in December »Updated: Jun 4, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
January is the month when Bethlehem sees the average lowest temperatures, with a high of 34°F (1.1°C) and a low of 21.6°F (-5.8°C).
In Bethlehem, during the entire year, the rain falls for 153 days and collects up to 26.81" (681mm) of precipitation.
January through May, October through December are months with snowfall.
Throughout the year, there are 26.7 snowfall days, and 14.49" (368mm) of snow is accumulated.
January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index.
The most humid month is February, with an average relative humidity of 82%.
February has the least sunshine of the year, with an average of 4.5h of sunshine.
March is the month with the most snowfall. Snow falls for 5 days and accumulates 4.13" (105mm) of snow.
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from EST to EDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from EDT to EST.
April and July, with an average relative humidity of 76%, are the least humid months.
The months with the highest UV index are May through July, with an average maximum UV index of 6.
In Bethlehem, snow does not fall in June through September.
The month with the longest days is June, with an average of 15h and 0min of daylight.
July is the warmest month, with the temperature often reaching an average high of 83.5°F (28.6°C) and an average low of 63.5°F (17.5°C).
The month with the most rainfall is July, when the rain falls for 16.2 days and typically aggregates up to 2.91" (74mm) of precipitation.
With an average of 10.4h of sunshine, July has the most sunshine of the year.
The month with the least rainfall in Bethlehem is September, when the rain falls for 11.8 days and typically collects 1.57" (40mm) of precipitation.
The month with the shortest days is December, with an average of 9h and 18min of daylight.
Average temperature
Bethlehem, PA
The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is January (34°F).
The month with the highest average low temperature is July (63.5°F).
The coldest month (with the lowest average low temperature) is January (21.6°F).
Average pressure
Bethlehem, PA
- Average pressure in January:
30.08"Hg - Average pressure in February:
30.05"Hg - Average pressure in March:
30.07"Hg - Average pressure in April:
29.98"Hg - Average pressure in May:
30.01"Hg - Average pressure in June:
29.94"Hg
- Average pressure in July:
29.96"Hg - Average pressure in August:
29.99"Hg - Average pressure in September:
30.06"Hg - Average pressure in October:
30.03"Hg - Average pressure in November:
30.12"Hg - Average pressure in December:
30.09"Hg
The month with the highest atmospheric pressure is November (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed
Bethlehem, PA
- Average wind speed in January:
8mph - Average wind speed in February:
7.9mph - Average wind speed in March:
8.1mph - Average wind speed in April:
7.9mph - Average wind speed in May:
6.2mph - Average wind speed in June:
5.8mph
- Average wind speed in July:
5.1mph - Average wind speed in August:
5mph - Average wind speed in September:
5.5mph - Average wind speed in October:
6.7mph - Average wind speed in November:
7mph - Average wind speed in December:
7.6mph
The windiest month (with the highest average wind speed) is March (8.1mph).
The calmest month (with the lowest average wind speed) is August (5mph).
Average humidity
Bethlehem, PA
The month with the highest relative humidity is February (82%).
The months with the lowest relative humidity are April and July (76%).
Average rainfall
Bethlehem, PA
- Average rainfall in January:
1.81" - Average rainfall in February:
1.69" - Average rainfall in March:
2.17" - Average rainfall in April:
2.44" - Average rainfall in May:
2.72" - Average rainfall in June:
2.4"
- Average rainfall in July:
2.91" - Average rainfall in August:
2.76" - Average rainfall in September:
1.57" - Average rainfall in October:
2.17" - Average rainfall in November:
1.93" - Average rainfall in December:
2.24"
The wettest month (with the highest rainfall) is July (2.91").
The driest month (with the least rainfall) is September (1.57").
Average rainfall days
Bethlehem, PA
- Average rainfall days in January:
7.8 days - Average rainfall days in February:
8.4 days - Average rainfall days in March:
11.8 days - Average rainfall days in April:
15.5 days - Average rainfall days in May:
17.8 days - Average rainfall days in June:
15.8 days
- Average rainfall days in July:
16.2 days - Average rainfall days in August:
15.3 days - Average rainfall days in September:
11.8 days - Average rainfall days in October:
12.4 days - Average rainfall days in November:
9.5 days - Average rainfall days in December:
10.7 days
The month with the highest number of rainy days is May (17.8 days).
The month with the least rainy days is January (7.8 days).
Average snowfall
Bethlehem, PA
- Average snowfall in January:
3.23" - Average snowfall in February:
3.7" - Average snowfall in March:
4.13" - Average snowfall in April:
0.16" - Average snowfall in May:
0.12" - Average snowfall in June:
0"
The month with the highest snowfall is March (4.13").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days
Bethlehem, PA
- Average snowfall days in January:
7.8 days - Average snowfall days in February:
7.8 days - Average snowfall days in March:
5 days - Average snowfall days in April:
0.4 days - Average snowfall days in May:
0.1 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0 days - Average snowfall days in October:
0.1 days - Average snowfall days in November:
0.7 days - Average snowfall days in December:
4.8 days
The months with the highest number of snowfall days are January and February (7.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight / Average sunshine
Bethlehem, PA
- Average daylight in January:
9h and 42min - Average daylight in February:
10h and 42min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 18min - Average daylight in May:
14h and 30min - Average daylight in June:
15h and 0min
- Average daylight in July:
14h and 42min - Average daylight in August:
13h and 42min - Average daylight in September:
12h and 30min - Average daylight in October:
11h and 6min - Average daylight in November:
9h and 54min - Average daylight in December:
9h and 18min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in January:
4h and 42min - Average sunshine in February:
4h and 30min - Average sunshine in March:
6h and 18min - Average sunshine in April:
8h and 0min - Average sunshine in May:
8h and 18min - Average sunshine in June:
9h and 36min
- Average sunshine in July:
10h and 24min - Average sunshine in August:
9h and 54min - Average sunshine in September:
8h and 48min - Average sunshine in October:
5h and 30min - Average sunshine in November:
5h and 30min - Average sunshine in December:
4h and 42min
The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).
Average sunshine days
Bethlehem, PA
- Average sunshine days in January:
18 days - Average sunshine days in February:
13.9 days - Average sunshine days in March:
14.3 days - Average sunshine days in April:
12.8 days - Average sunshine days in May:
11 days - Average sunshine days in June:
12.3 days
- Average sunshine days in July:
11.8 days - Average sunshine days in August:
13.4 days - Average sunshine days in September:
15.6 days - Average sunshine days in October:
16.8 days - Average sunshine days in November:
18.9 days - Average sunshine days in December:
17.2 days
The month with the most sunshine days is November (18.9 days).
The month with the least sunshine days is May (11 days).
Average UV index
Bethlehem, PA
The months with the highest UV index are May, June and July (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover
Bethlehem, PA
The month with the most cloud cover is February (Cloud cover 51).
The month with the least cloud cover is July (Cloud cover 34).
Average visibility
Bethlehem, PA
The months with the highest visibility are April, June and November (6mi).
The months with the lowest visibility are January, February, March, May, July, August, September, October and December (5mi).
