Climate and monthly weather forecast
Bethlehem, PA

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A tranquil setting of dry trees and neat fields behind this large hall in the Lehigh University in Bethlehem, Pennsylvania
A tranquil setting of dry trees and neat fields behind this large hall in the Lehigh University in Bethlehem, Pennsylvania

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 »

Frequently asked questions

What are the coldest months?

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).

How many days does it rain?

In Bethlehem, during the entire year, the rain falls for 153 days and collects up to 26.81" (681mm) of precipitation.

When does it snow?

January through May, October through December are months with snowfall.

How many days does it snow in Bethlehem?

Throughout the year, there are 26.7 snowfall days, and 14.49" (368mm) of snow is accumulated.

What is the month with the lowest UV index?

January through March, November and December, with an average maximum UV index of 2, are months with the lowest UV index.

What is the most humid month?

The most humid month is February, with an average relative humidity of 82%.

What is the month with the least sunshine in Bethlehem?

February has the least sunshine of the year, with an average of 4.5h of sunshine.

What is the snowiest month?

March is the month with the most snowfall. Snow falls for 5 days and accumulates 4.13" (105mm) of snow.

When is Daylight Saving Time (DST)?

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.

What is the least humid month in Bethlehem?

April and July, with an average relative humidity of 76%, are the least humid months.

When is the highest UV index?

The months with the highest UV index are May through July, with an average maximum UV index of 6.

When it does not snow?

In Bethlehem, snow does not fall in June through September.

When are the longest days?

The month with the longest days is June, with an average of 15h and 0min of daylight.

What month is the hottest?

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).

What is the rainiest month?

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.

What month has the most sunshine?

With an average of 10.4h of sunshine, July has the most sunshine of the year.

What is the driest month?

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.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 18min of daylight.

Average temperature
Bethlehem, PA

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 - Bethlehem, PA

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 - Bethlehem, PA

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

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 - Bethlehem, PA

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 - Bethlehem, PA

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 - Bethlehem, PA

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 - Bethlehem, PA

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 / Average sunshine - Bethlehem, PA

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).

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 - Bethlehem, PA

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

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 visibility
Bethlehem, PA

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).

Bethlehem, Pennsylvania, USA

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