Climate and monthly weather forecast
Affton, MO

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The climate of Affton

Positioned in Missouri, USA, Affton embraces a humid subtropical climate, known as Cfa according to the Köppen climate classification, without a dry season. The climate features substantial humidity that persists throughout the year, peaking at 78% in May and recording the least in October at 71%. Temperatures in this region vary considerably throughout the year, from a high of 86.9°F (30.5°C) in July to a low of 25°F (-3.9°C) in January.

Rainfall is a constant yet variable feature of the climatic conditions of Affton. Monthly averages range from a high of 3.94" (100mm) in May to a low of 1.77" (45mm) in both February and November. Moreover, days with rain also oscillate within the year, reaching a high of 16.9 in July and descending to a low of 6.8 in January and February.

Despite the predominantly humid climate, snow graces Affton during winter with an average of 2.6" (66mm) in February. However, the presence of snow is not an all-year-round phenomenon. From May through October, no snowfall is observed. The rest of the year experiences a tapering amount. The daylight enjoyed in Affton also varies throughout the year with a longer 14.8 hours in June and a shorter 9.5 hours in December.

The best time to visit Affton

The optimal time for a trip to Affton, Missouri heavily depends on personal preferences regarding temperature, precipitation, and daylight hours. For instance, those who thrive in warmer weather may find July and August with high temperatures peaking at 86.9°F (30.5°C) and 85.6°F (29.8°C) respectively best suited for their visit. Similarly, daylight hours during this period are also the longest, at around 14.5 to 14.8 hours per day, allowing for more time to explore.

For visitors who enjoy moderate temperatures, May’s average temperature range of 57.7°F (14.3°C) to 75.4°F (24.1°C), combined with about 14.3 hours of daylight and a peak relative humidity, may provide a quintessential springtime experience. Rainfall during this period is at its maximum of 3.94" (100mm), and as such, the environment will be lush and vibrant, optimal for nature exploration and outdoor activities.

The worst time to visit Affton

The less desirable period to visit Affton would be during winter months from December to February where temperatures take a significant dip, reaching their lowest at 25°F (-3.9°C) in January. These months observe the shortest daylight hours, ranging from 9.5 to 10.8 hours. January in particular witnesses a high frequency of snowfall with an average of 4.8 days and measures 2.2" (56mm) in snowfall.

Compared to the rest of the year, this period has reduced visibility due to limited daylight. The increasing cloud cover, touching a peak of 51% in December, further reduces the visibility. Wind speeds also surge during this period, reaching their yearly maximum of 9.1mph (14.6km/h) in January.

Spring weather in Affton

Spring in Affton, extending from March to May, introduces escalating temperatures that range from highs of 54.5°F (12.5°C) in March to 75.4°F (24.1°C) in May. The lows during this period also emulate a similar pattern, commencing from 38.1°F (3.4°C) in March and adding up to 57.7°F (14.3°C) in May. Affton experiences its peak relative humidity of 78% in May and an appropriate amount of rainfall amounting to 3.94" (100mm), adding life to the vegetative landscapes.

Summer weather in Affton

Summer in Affton, Missouri, from June to August, is characterized by warm temperatures with highs peaking at an average of 86.9°F (30.5°C) in July. The humidity levels during this period hover around 76%, lending the area a rich, warm atmosphere. The period is also marked by generous daylight hours, up to 14.8 hours in June, permitting ample time for exploring and outdoor activities.

Autumn weather in Affton

Autumn enters Affton in September and departs in November, gradually pulling down the temperature from 79.7°F (26.5°C) in September to 53.8°F (12.1°C) in November. Concurrently, the amount of daylight dwindles from 12.4 hours in September to 10.1 hours in November. Despite the gradual descent into cooler temperatures, humidity remains fairly constant from 73% in September to 72% in November.

Winter weather in Affton

Winter in Affton brings about colder temperatures from 43.2°F (6.2°C) to 37.9°F (3.3°C) high and 25°F (-3.9°C) to 28.4°F (-2°C) low between December and February. The daylight hours decrease to their lowest point of the year, with 9.5 hours in December. Snowfall is also observed, and January records the maximum amount of 2.2" (56mm) and 4.8 days of snowfall. The relative humidity during this season stays slightly elevated, fluctuating from 76% to 75%.

Weather in January

January's weather in Affton, Missouri shifts from the colder conditions of December. The frosty winter climate persists with snow-covered landscapes due to an average snowfall of 2.2" (56mm). It's a month known for its white scenery and chill, perfect for winter activities. Weather in January »

Weather in February

As the calendar turns to February, the weather conditions remain on the cold side in Affton, Missouri but there’s a gradual transition towards spring-like conditions. There's an increase of one degree from January’s UV index, indicating longer and brighter days. Weather in February »

Weather in March

In March, the chilly grip of winter begins to lose its hold on Affton. This is reflected in the declining snowfall, with an average of just 1.18" (30mm) for the month. March ushers in the spring season, the onset of blooming flowers, and greening trees. Weather in March »

Weather in April

The weather in April in Affton, Missouri, is known for its mildness and the noticeable absence of snowfall. April marks the complete transition to springtime, presenting a relief from the cold winter temperatures. As fresh leaves unfurl on trees and more flowers bloom, bird song accompanies the increasingly vibrant outdoor activity. Weather in April »

Weather in May

May is the onset of warmer weather in Affton, Missouri. The month stands out due to its higher rainfall, reaching an apex at an average 3.94" (100mm). This month sees an escalation in temperatures and humidity, marking the transition into the summer season. Weather in May »

Weather in June

June in Affton, Missouri, signals the full flourishing of the summer season. The prolonged daylight hours and the increasing temperature sets the stage for outdoor activities. On the other hand, June can be a humid month, making hydration and sunscreen vital elements of any outdoor plan. Weather in June »

Weather in July

July is typically the hottest month in Affton, Missouri, with average temperatures peaking at 86.9°F (30.5°C). There’s a certain intensity that comes with July, making it critical to find effective ways to beat the heat. Whether it's ice-cold lemonade, swaying on a porch swing, or sitting by a pool, the month invites relaxation. Weather in July »

Weather in August

Members of the Affton community can still expect to relish in the heat of the summer sun in August. Despite the high temperatures, there's an underlying knowledge of the impending end of summer and the onset of fall. It’s a period of cherishing the still long daylight hours and the freedom they bring before the transition of seasons. Weather in August »

Weather in September

In September, Affton, Missouri sees a dip in temperatures, marking the change from summer to fall. The weather shifts drive many to engage in activities that align with this transitional season. Whilst the summer heat starts to wind down, the cooling evenings cultivate a sense of tranquility and peace. Weather in September »

Weather in October

October’s weather is marked by the falling temperatures, the shortening days, and the vibrant foliage. Iconic for its spectacular display of fall colors, it sees Affton turning into a painter's palette of reds, oranges, and yellows. Weather in October »

Weather in November

November is recognized for its declining temperatures with an average low of 37.9°F (3.3°C). This month is a clear indicator of the impending onset of winter in Affton. As the leaves continue to fall, November marks the transition from autumn's vibrant colors to the stark beauty of winter. Weather in November »

Weather in December

December conjures images of chilling temperatures, early sunsets, and most notably, the return of snowfall. The falling flakes add to the charm of holiday decorations, giving Affton a picturesque setting. It's a month filled with beautiful holiday lights, celebrations, and the magic that comes with the Yuletide season. Weather in December »
Updated: Aug 31, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What month is the coldest?

January, on average, is the coldest month, registering a high temperature of 37.9°F (3.3°C) and a low of 25°F (-3.9°C).

How much does it rain?

Throughout the year, there are 146.1 rainfall days, and 32.36" (822mm) of precipitation is accumulated.

When does it snow?

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

How much does it snow in Affton?

In Affton, during the entire year, snow falls for 15.3 days and aggregates up to 8.27" (210mm) of snow.

What is the month with the least sunshine?

The month with the least sunshine is January, with an average of 4.5h of sunshine.

What is the month with the lowest UV index?

The months with the lowest UV index are January, February and December, with an average maximum UV index of 2.

What is the driest month in Affton?

February and November are months with the least rain when the rain falls for 6.8 days and typically aggregates up to 1.77" (45mm) of rain.

When does it snow the most?

The month with the most snowfall is February, when snow falls for 4.8 days and typically aggregates up to 2.6" (66mm) 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 CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.

When it does not snow?

In Affton, snow does not fall in April through October.

What is the most humid month?

With an average relative humidity of 78%, May is the most humid month.

What is the rainiest month?

May is the month with the most rainfall. Rain falls for 16.8 days and accumulates 3.94" (100mm) of precipitation.

What are the months with the highest UV index?

May through August, with an average maximum UV index of 6, are months with the highest UV index in Affton.

When are the longest days?

The month with the longest days is June, with an average of 14h and 48min of daylight.

What month has the most sunshine?

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

What is the warmest month?

July, characterized by an average high temperature of 86.9°F (30.5°C) and a low temperature of 69.3°F (20.7°C), is generally the warmest month.

What is the least humid month?

With an average relative humidity of 71%, October is the least humid month in Affton, Missouri.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 30min of daylight.

Average temperature
Affton, MO

Average temperature - Affton, MO

The warmest month (with the highest average high temperature) is July (86.9°F).
The month with the lowest average high temperature is January (37.9°F).

The month with the highest average low temperature is July (69.3°F).
The coldest month (with the lowest average low temperature) is January (25°F).

Average pressure
Affton, MO

Average pressure - Affton, MO

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed
Affton, MO

Average wind speed - Affton, MO

The windiest month (with the highest average wind speed) is January (9.1mph).
The calmest months (with the lowest average wind speed) are July and August (5.5mph).

Average rainfall
Affton, MO

Average rainfall - Affton, MO

The wettest month (with the highest rainfall) is May (3.94").
The driest months (with the least rainfall) are February and November (1.77").

Average rainfall days
Affton, MO

Average rainfall days - Affton, MO

The month with the highest number of rainy days is July (16.9 days).
The months with the least rainy days are January and February (6.8 days).

Average snowfall
Affton, MO

Average snowfall - Affton, MO

The month with the highest snowfall is February (2.6").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days
Affton, MO

Average snowfall days - Affton, MO

The months with the highest number of snowfall days are January and February (4.8 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight / Average sunshine
Affton, MO

Average daylight / Average sunshine - Affton, MO

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).

Average sunshine days
Affton, MO

Average sunshine days - Affton, MO

The month with the most sunshine days is January (20.9 days).
The month with the least sunshine days is June (11.6 days).

Average UV index
Affton, MO

Average UV index - Affton, MO

The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).

Average visibility
Affton, MO

Average visibility - Affton, MO

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).

Affton, Missouri, USA

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