Climate and monthly weather forecast
Williamsport, PA

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The climate of Williamsport

Classified under the Köppen climate classification as a humid continental climate, Williamsport, Pennsylvania experiences no dry season, with rainfall distributed evenly throughout the year. The city's geographical position exposes it to varying weather patterns all year round. Weather parameters such as temperature, humidity, rainfall, and daylight hours show significant changes as seasons transition.

Temperature highs gradually rise from an average high of 30.6°F (-0.8°C) in January to a peak of 81.7°F (27.6°C) in July, before descending back to 36.7°F (2.6°C) by December. A similar trend occurs in temperature lows, with the coolest month being January at an average low of 18.9°F (-7.3°C), and July having the warmest nights at an average of 59.2°F (15.1°C).

In terms of humidity, the relative averages swing from 77% to 84%, reflecting a consistently high level of moisture in the air. Precipitation events are relatively frequent but moderate, with rainfall ranging between 0.94" (24mm) and 1.93" (49mm) monthly. The number of rainfall days falls between 7.5 days and 16.6 days in a month, indicating regular overcast conditions. This is further corroborated by the percentage of cloud cover, which varies from 35% to 60%.

Interestingly, Williamsport also experiences snowfall, averaging between 2.28" (58mm) and 0.1" (3mm). Snowfall primarily occurs from January to March and then briefly in November and December, with snowless skies from April to October.

The best time to visit Williamsport

Tourists interested in milder temperatures and less rainfall might find that the best time to visit Williamsport is between May and October. During this period, daytime temperatures range from 56.5°F (13.6°C) to 79.2°F (26.2°C), with significantly reduced rainfall levels, averaging from 1.5 to 1.85" (47mm). The length of daylight also reaches its maximum in these months, enhanced by sunshine hours averaging between 8.3 hours and 10.1 hours per day. Meanwhile, humidity levels drop slightly, resulting in more pleasant weather overall.

The worst time to visit Williamsport

The colder months of January and February present the most challenging weather conditions. With the lowest average high and low temperatures, ranging from 18.9°F (-7.3°C) to 34.5°F (1.4°C), visitors can expect snowy and icy scenarios, particularly as snowfall reaches its peak within these months. Rainfall also consistently hovers around the 0.98" (25mm) mark with more frequent rainy days.

Spring weather in Williamsport

Spring in Williamsport marks a steady rise in temperatures, with average highs ranging between 44.2°F (6.8°C) in March to 68.4°F (20.2°C) by May. Correspondingly, nighttime temperatures rise from 27.7°F (-2.4°C) to 48°F (8.9°C). While rainfall does increase during this period, from 1.1" (28mm) in March to 1.85" (47mm) in May, the length of daylight also notably extends from 12 hours to 14.5 hours.

Summer weather in Williamsport

The summer months, June through August, promise warm sunny days with average highs peaking at 81.7°F (27.6°C) in July. Even nights remain warm, averaging between 54.7°F (12.6°C) and 59.2°F (15.1°C). Rainfall remains relatively constant around 1.57" (40mm) to 1.69" (43mm). The season is characterized by long, sunny days, with the longest day in June giving more than 15 hours of daylight and sunshine acquiring a peak prominence of 10.1 hours in July.

Autumn weather in Williamsport

The autumn months in Williamsport witness a gradual decrease in temperatures from the high of 72.1°F (22.3°C) in September to 46.2°F (7.9°C) in November. The night temperature also descends quite noticeably from 51.4°F (10.8°C) to 32.4°F (0.2°C). Rainfall sees a slight decrease from September through November, maintaining an average of 1.44" (37mm). Sunshine hours also dwindle, contrasting the abundant sunshine of the summer, reaching as low as 5 hours per day in November.

Winter weather in Williamsport

Winters in Williamsport are cold and frequently snowy. Daily average temperatures range from 30.6°F (-0.8°C) to 36.7°F (2.6°C), with nightly lows resting between 18.9°F (-7.3°C) and 26.6°F (-3°C). Snowfall is a common occurrence, especially in January, with an average accumulation of 2.13" (54mm). Daylight becomes scarce during this season, with the shortest day seeing only 9.3 hours of light, and sunshine hours can be as sparse as 3.7 hours per day.

Weather in January

January is the start of the year and embraces Williamsport with a quintessential winter scene. The city encounters significant snowfall with an average snowfall depth of 2.13" (54mm) coupled with the lowest temperatures of the year. Weather in January »

Weather in February

As Williamsport navigates through February, a slight increase in temperature is noticed though the winter chill still lingers. February is another month where snowfall is encountered, albeit slightly less than January at around 2.28" (58mm). Weather in February »

Weather in March

March marks the onset of spring in Williamsport. The snow has mostly started to retreat, paving the way for a change in atmosphere with rainfall recordings standing at an average of 1.1" (28mm). The increases in temperature to a high of 44.2°F (6.8°C) and a low of 27.7°F (-2.4°C) bring a noticeable difference from the winter months. Weather in March »

Weather in April

April in Williamsport sees a definitive spring vibe. A significant leap in temperature can be observed, culminating in a high of 56.5°F (13.6°C) and a low of 37.8°F (3.2°C). A noticeable transition from snowfall to rainfall transpires, with little to no snowfall registered and rainfall climbing to 1.93" (49mm). Weather in April »

Weather in May

May introduces Williamsport to warmer temperatures, signifying the approaching summer. With average high temperatures reaching a comfortable 68.4°F (20.2°C), the outdoor scene starts bustling with people. Clouds get sparser, setting the stage for about 8.3 hours of sunshine on an average day. Weather in May »

Weather in June

June welcomes the summer in Williamsport with a noticeable rise in temperatures. With the highest daylight hours recorded in a month reaching 15.1 hours, outdoor activity is at its peak. Temperatures continue to rise and settle around a high of 76.1°F (24.5°C). Weather in June »

Weather in July

July brings forth the hottest weather conditions for Williamsport in the year. Fluctuations in temperature are minimal, with an average recorded high of 81.7°F (27.6°C), the highest for the year. Despite the consistent sunshine, the air clings to a high humidity level making conditions feel hotter than recorded. Weather in July »

Weather in August

August in Williamsport continues the summer spell but brings a slight drop in temperature compared to July. The fading summer heat still allows for plenty of outdoor activities, with suitable climate conditions throughout the month. Weather in August »

Weather in September

September signals the onset of autumn in Williamsport. Waning summer warmth leaves the climate pleasant, with an average temperature high of 72.1°F (22.3°C) during the day. This month marks a visible shift in the weather pattern as daylight hours start to shrink. Weather in September »

Weather in October

October brings a soothing chill to Williamsport as the heart of autumn sets in. A sharp decline in temperature is noticed with an average high of 59.4°F (15.2°C). This month showcases the turning leaves of the Pennsylvania autumn, as vibrant colors paint the cityscape. Weather in October »

Weather in November

November in Williamsport initiates the early onset of winter weather. With a discernable dip in temperatures, reaching a high of 46.2°F (7.9°C), residents prepare for the cold months ahead. The rainfall reduces to 0.94" (24mm), hinting at the imminent shift to wintery conditions. Weather in November »

Weather in December

December graces Williamsport with a taste of winter magic. The city captures the charm of the season with a meaningful increase in snowfall, an average depth of 1.38" (35mm) recorded. The temperature dips to a chilly 36.7°F (2.6°C) high, adding to the festive freezing spirit. Weather in December »

Frequently asked questions

What part of the year is the coldest?

Williamsport's coldest temperatures are experienced in January, with average high temperatures of 30.6°F (-0.8°C) and lows of 18.9°F (-7.3°C).

How many days does it rain?

In Williamsport, during the entire year, the rain falls for 145.2 days and collects up to 16.57" (421mm) of precipitation.

When does it snow?

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

How much does it snow?

In Williamsport, during the entire year, snow falls for 39.1 days and aggregates up to 7.56" (192mm) of snow.

What are the months with the least sunshine?

January and February, with an average of 3.7h of sunshine, are months with the least sunshine.

What is the month with the lowest UV index?

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

What is the most humid month?

With an average relative humidity of 84%, February is the most humid month in Williamsport, Pennsylvania.

What is the snowiest month?

The month with the most snowfall is February, when snow falls for 10.1 days and typically aggregates up to 2.28" (58mm) 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?

April and July, with an average relative humidity of 77%, are the least humid months.

What is the wettest month?

The month with the most rainfall is April, when the rain falls for 15 days and typically aggregates up to 1.93" (49mm) of precipitation.

When it does not snow in Williamsport?

In Williamsport, Pennsylvania, snow does not fall in May through September.

When are the longest days in Williamsport?

With an average of 15h and 6min of daylight, June has the longest days of the year.

What are the warmest months?

Williamsport's July weather, marked by an average high temperature of 81.7°F (27.6°C) and an average low temperature of 59.2°F (15.1°C), is the warmest in the year.

What month has the most sunshine?

The month with the most sunshine is July, with an average of 10.1h of sunshine.

When is the highest UV index?

The month with the highest UV index is July, with an average maximum UV index of 6.

What is the driest month?

November is the month with the least rainfall. Rain falls for 8.6 days and accumulates 0.94" (24mm) of precipitation.

What is the month with the shortest days in Williamsport?

December has the shortest days of the year, with an average of 9h and 18min of daylight.

Average temperature
Williamsport, PA

Average temperature - Williamsport, PA

The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (30.6°F).

The month with the highest average low temperature is July (59.2°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).

Average pressure
Williamsport, PA

Average pressure - Williamsport, PA

The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

Average wind speed
Williamsport, PA

Average wind speed - Williamsport, PA

The windiest months (with the highest average wind speed) are January, March and April (7.5mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).

Average humidity
Williamsport, PA

Average humidity - Williamsport, PA

The month with the highest relative humidity is February (84%).
The months with the lowest relative humidity are April and July (77%).

Average rainfall
Williamsport, PA

Average rainfall - Williamsport, PA

The wettest month (with the highest rainfall) is April (1.93").
The driest month (with the least rainfall) is November (0.94").

Average rainfall days
Williamsport, PA

Average rainfall days - Williamsport, PA

The month with the highest number of rainy days is May (16.6 days).
The month with the least rainy days is February (7.5 days).

Average snowfall
Williamsport, PA

Average snowfall - Williamsport, PA

The month with the highest snowfall is February (2.28").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days
Williamsport, PA

Average snowfall days - Williamsport, PA

The month with the highest number of snowfall days is January (11.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight / Average sunshine
Williamsport, PA

Average daylight / Average sunshine - Williamsport, PA

The month with the longest days is June (Average daylight: 15h and 6min).
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 6min).
The months with the least sunshine are January and February (Average sunshine: 3h and 42min).

Average sunshine days
Williamsport, PA

Average sunshine days - Williamsport, PA

The month with the most sunshine days is November (18.7 days).
The month with the least sunshine days is May (11.8 days).

Average UV index
Williamsport, PA

Average UV index - Williamsport, PA

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).

Williamsport, Pennsylvania, USA

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