Climate and monthly weather forecast
Duncan, OK

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The climate of Duncan

Duncan is in the Köppen climate classification Cfa zone, which is described as a humid subtropical region with no dry season. Unsurprisingly, this Oklahoma-based city experiences a wide spectrum of weather conditions throughout the annual cycle. These stretch from colder winter months with potential snowfall to swelteringly warm summer months.

Throughout the year, a relatively high level of humidity is observed, with percentages ranging between 55% in August and 73% in May. Rainfall varies greatly, with the highest precipitation occurring in May—4.37" (111mm). Duncan also sees its least rainfall in February, measuring only 1.02" (26mm). It can snow in Duncan, but snowfall occurs mainly in the winter months, peaking in February with 1.3" (33mm).

Temperatures in Duncan can take quite a swing over the year as well, reaching a high of 95°F (35°C) in August and sinking to a low of 33.6°F (0.9°C) in January. Monthly average visibility remains consistent at 6 miles, making it usually easy for residents and visitors alike to enjoy the scenic surrounding areas. Wind speeds in Duncan are relatively steady, fluctuating from 8.3mph (13.4km/h) to 11.6mph (18.7km/h), with maximum speeds recorded between 11.7mph (18.8km/h) and 12.6mph (20.3km/h).

The best time to visit Duncan

People looking to experience Duncan at its warmest might want to consider visiting between June and August. Temperatures during this period are usually between 79.3°F (26.3°C) and 95°F (35°C), providing conditions perfect for outdoor activities. Relative humidity is comparatively low in these months, from 55% to 67%, which contributes to a comfortable atmosphere. Additionally, sunshine prevails with 10.7 hours to 11.1 hours of sunlight per day.

The worst time to visit Duncan

Duncan's winter months of December to February bear the coldest temperatures, falling between 33.6°F (0.9°C) and 54.3°F (12.4°C). Occasional snowfall also happens in this period, with 0.79" (20mm) in December and 1.3" (33mm) in February. While these conditions could be attractive to some, those averse to cold weather and potential snow-driven activities might opt to schedule their visit for a different time of the year.

Spring weather in Duncan

Springtime in Duncan sees a gradual increase in temperature, from 51.3°F (10.7°C) in March to a warm 79.3°F (26.3°C) in May. Rainfall can reach as high as 4.37" (111mm) in May, but usually hovers around 1.85" (47mm) in March. Humidity levels moderately rise, from 64% in March to 73% in May while wind patterns remain fairly consistent, averaging between 10.4mph (16.7km/h) and 11.6mph (18.7km/h).

Summer weather in Duncan

Summers in Duncan are known for their warm temperatures. They can range from 86.2°F (30.1°C) in September to 95°F (35°C) in August. Remarkably, rainfall is highest in June and September, recording 1.89" (48mm) and 2.64" (67mm) respectively. However, there is a sharp drop in rainfall during July and August, as Duncan receives only 2.17" (55mm) and 1.61" (41mm) of rain respectively. Sunshine is abundant, with an average of 10.8 hours of sunlight in August.

Autumn weather in Duncan

Autumn in Duncan witnesses a decrease in temperatures from the preceding summer months. October's average high temperature is 72.9°F (22.7°C), which cools down to 61.7°F (16.5°C) by November. The rainfall increases gradually from 2.6" (66mm) in October to 1.06" (27mm) in November. The average number of sunny days starts to decline, from 19.5 days in October to 22 days in November, but still provides ample time to enjoy the city's outdoors.

Winter weather in Duncan

Winters in Duncan are characterized by moderately cold weather, with temperatures ranging from 51.3°F (10.7°C) in December to 33.6°F (0.9°C) in January. Although snowfall can occur, it typically remains below 1.3" (33mm) throughout the winter months. December experiences the highest number of sunshine days, with a count of 23.2 days, while January settles at 24.3 days. Wind speeds generally range from 9.7mph (15.6km/h) to 10.3mph (16.6km/h), making winter in Duncan a relatively calm season.

Weather in January

January in Duncan, Oklahoma tends to be the coolest month of the year. The chill even extends to daylight, with January having the shortest daylight duration out of the entire year. The familiar sights of snowflakes can be observed on about 1.3 days, with the clouds covering 26% of the sky. Weather in January »

Weather in February

As winter drags on, the signs of an imminent spring emergence can be felt in February. The temperature starts to inch upwards from the previous month. Duncan often tosses aside its snow blanket in February, the average snowfall dwindling to 1.3" (33mm). Weather in February »

Weather in March

Come March, the weather is hinting at the shift from winter to spring. With an average high nudging up to 64.9°F (18.3°C), people start to shed their heavy winter coats. The amount of sunshine also increases, contributing to longer days, a factor that excites outdoor enthusiasts. Weather in March »

Weather in April

By April, Duncan, Oklahoma is in the full swing of spring. Temperatures continue to show a steady, noticeable rise, with the average high reaching up to 72.3°F (22.4°C), and the low averages at a mild 52.5°F (11.4°C). April brings in a high amount of rainfall, with an average of 3.07" (78mm) over an expected 11.9 days. Weather in April »

Weather in May

May is a transition month where the last whisper of spring gives way to summer in Duncan. The weather continues to show sunny and warm characteristics, signifying the start of the long days of summer. A high relative humidity often hangs in the air, creating a truly tropical feeling. Weather in May »

Weather in June

June signifies the onset of summer in Duncan, Oklahoma. It brings with it longer days and soaring temperatures. Sun worshippers enjoy this month, which heralds in the highest levels of daylight at 14.4 hours. Sunshine is generous, bathing the city in approximately 10.7 hours of sunny glory. Weather in June »

Weather in July

July is the heart of summer in Duncan, with temperatures often hitting their peak. The heat does not go unnoticed. July bears the crown of the hottest month, with scorching average highs and lows hovering around 94.6°F (34.8°C) and 73.9°F (23.3°C) respectively. Weather in July »

Weather in August

August holds on to the reigns of summer, continuing with warm and sunny weather. The vibrant hues of summer remain strong, even as signs of the approaching autumn subtly begin to hint at a shift. Despite recording the highest temperature of the year at 95°F (35°C), August also sees a decrease in relative humidity. Weather in August »

Weather in September

September nudges towards fall but continues to hold on to the last tendrils of summer. The change in Duncan's weather is more noticeable, with temperatures cooling, and the daylight hours reducing to 12.4. Despite the transition, the maximum temperature averages still hit a high of 86.2°F (30.1°C) with the minimum settling around a comfortable 66.9°F (19.4°C). Weather in September »

Weather in October

October ushers in the full effect of fall. The vibrant colors of summer fade, replaced by the richness of the fall foliage. The drop in temperatures continues, and they begin to trend towards a cooler climate. Though rainfall is frequent at 2.6" (66mm), October experiences a slightly higher sunshine duration of 7 hours as compared to September’s 8.3 hours. Weather in October »

Weather in November

In November, the crispness of fall is tangible. The previous mild weather transitions further towards the colder side, as winter approaches. Wind speeds slightly heighten to an average of 10.3mph (16.6km/h), adding an extra bite to the dropping temperatures. Weather in November »

Weather in December

December is when the full force of winter sets in. The season of snowfalls returns to Duncan with an average snowfall of 0.51" (13mm). The shorter daylight hours and the colder temperatures hint at the longer nights and the winter chill. Weather in December »
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Frequently asked questions

What part of the year is the coldest in Duncan?

The yearly lowest temperatures in Duncan occur in January and December, averaging a high-temperature of 51.3°F (10.7°C).

How much does it rain in Duncan?

In Duncan, Oklahoma, during the entire year, the rain falls for 113.4 days and collects up to 24.61" (625mm) of precipitation.

When does it snow in Duncan?

January through April, November and December are months with snowfall.

How many days does it snow in Duncan?

Throughout the year, in Duncan, Oklahoma, there are 5.1 snowfall days, and 3.03" (77mm) of snow is accumulated.

What is the driest month in Duncan?

The month with the least rainfall is February, when the rain falls for 6.8 days and typically collects 1.02" (26mm) of precipitation.

When does it snow the most in Duncan?

The month with the most snowfall is February, when snow falls for 1.8 days and typically aggregates up to 1.3" (33mm) of snow.

When is Daylight Saving Time (DST) in Duncan?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Duncan, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.

What is the most humid month in Duncan?

May is the most humid month in Duncan, with an average relative humidity of 73%.

What is the wettest month in Duncan?

The month with the most rainfall is May, when the rain falls for 13.5 days and typically aggregates up to 4.37" (111mm) of precipitation.

When it does not snow in Duncan?

May through October are months without snowfall.

When are the longest days in Duncan?

The month with the longest days in Duncan is June, with an average of 14h and 24min of daylight.

What are the months with the highest UV index in Duncan?

The months with the highest UV index in Duncan are June through August, with an average maximum UV index of 7.

What month has the most sunshine in Duncan?

With an average of 11.1h of sunshine, July has the most sunshine of the year in Duncan.

What is the warmest month in Duncan?

August, recognised by an average high temperature of 95°F (35°C) and a low of 73.6°F (23.1°C), is Duncan's warmest month.

What is the least humid month in Duncan?

With an average relative humidity of 55%, August is the least humid month in Duncan, Oklahoma.

What is the month with the shortest days in Duncan?

December has the shortest days of the year, with an average of 9h and 54min of daylight.

What is the month with the least sunshine in Duncan?

December has the least sunshine of the year in Duncan, Oklahoma, with an average of 6h of sunshine.

When is the lowest UV index in Duncan?

The month with the lowest UV index in Duncan, Oklahoma, is December, with an average maximum UV index of 2.

Average temperature
Duncan, OK

Average temperature - Duncan, OK

The warmest month (with the highest average high temperature) is August (95°F).
The months with the lowest average high temperature are January and December (51.3°F).

The month with the highest average low temperature is July (73.9°F).
The coldest month (with the lowest average low temperature) is January (33.6°F).

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Average pressure
Duncan, OK

Average pressure - Duncan, OK

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).

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Average wind speed
Duncan, OK

Average wind speed - Duncan, OK

The windiest month (with the highest average wind speed) is April (11.6mph).
The calmest months (with the lowest average wind speed) are July, August and September (8.3mph).

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Average rainfall
Duncan, OK

Average rainfall - Duncan, OK

The wettest month (with the highest rainfall) is May (4.37").
The driest month (with the least rainfall) is February (1.02").

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Average rainfall days
Duncan, OK

Average rainfall days - Duncan, OK

The month with the highest number of rainy days is May (13.5 days).
The month with the least rainy days is January (5 days).

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Average snowfall
Duncan, OK

Average snowfall - Duncan, OK

The month with the highest snowfall is February (1.3").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days
Duncan, OK

Average snowfall days - Duncan, OK

The month with the highest number of snowfall days is February (1.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average daylight / Average sunshine
Duncan, OK

Average daylight / Average sunshine - Duncan, OK

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).

The month with the most sunshine is July (Average sunshine: 11h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 0min).

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Average sunshine days
Duncan, OK

Average sunshine days - Duncan, OK

The month with the most sunshine days is January (24.3 days).
The month with the least sunshine days is May (15.7 days).

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Average visibility
Duncan, OK

Average visibility - Duncan, OK

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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Duncan, Oklahoma, USA

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