Climate and monthly weather forecastDecorah, IA
Climate and monthly weather forecast
The climate of Decorah
Decorah, Iowa dwells in the Köppen climate classification as Dfa. This indicates a Humid continental climate, no dry season, with hot summers. This global climate sector places Decorah near higher latitudes, causing the town to experience a clash of warm and chilly months throughout the annual cycle.Within the year, Decorah's climate cycles through a broad temperature range, from a frigid 9.7°F (-12.4°C) in the coldest months to pleasantly warm 78.4°F (25.8°C) during the hottest phase. In this fluctuating climate, humidity levels typically remain above 76%, with only minor variations throughout the year.
Rainfall infiltrates the 12-month cycle erratically. The wettest period, with 5.04" (128mm) of rain, shows its face in June, while January and February only offer a meager 1.1 and 1.26" (32mm) respectively. Correspondingly, maximum precipitation days occur during May and June, when the region endures rainfall for approximately 20.3 days.
Distinct seasonal variations are visible in Decorah's overall weather patterns. During winter, it's not uncommon to witness 5.63" (143mm) of snowfall in January and 5.98" (152mm) in February. Winter days can be quite short, with only 9 hours of daylight in core winter months, while the long summer days provide an ample 15.4 hours of daylight.
The best time to visit Decorah
Those aspiring to visit Decorah would find the period between May and September most favorable. During this span, the temperature rises to a comfortable range from 65.7°F (18.7°C) to 78.4°F (25.8°C), offering ideal conditions for outdoor activities and exploration. Moreover, these months stand out for their vast daylight hours, stretching 14.7 to 15.4 hours, enabling visitors to get the most out of their day.The worst time to visit Decorah
The least advisable period to plan a visit to Decorah is around mid-winter, from December to February. These months can be inherently harsh, with average low temperatures dipping to a frigid 9.7°F (-12.4°C) to 18.3°F (-7.6°C). This period also carries the burden of maximum snowfall, reaching up to 5.98" (152mm) in February, making outdoor activities hard to navigate.Spring weather in Decorah
Courtship with Spring in Decorah usually presents a massive shift from the chilling winter. Temperatures begin to rise moderately, achieving highs around 41°F (5°C) to 65.7°F (18.7°C) from March to May. As Spring progresses, daylight extends from 12 hours in March to an ample 14.7 hours in May. Do take note that April marks the onset of the rainfall season, with precipitation rising up to 3.39" (86mm).Summer weather in Decorah
Summers in Decorah are typically warm and extended. The mercury starts its ascent in June, with average highs hitting the 75°F (23.9°C) mark. July sees the peak with average highs reaching 78.4°F (25.8°C). The rainfall too is generous, peaking at 5.04" (128mm) in June. However, the region enjoys ample sunshine, notably with 15.4 hours of daylight in June and maximum UV index of 5 through the summer.Autumn weather in Decorah
Autumn in Decorah begins to reverse the summer warmth, showcasing falling temperatures from 70.7°F (21.5°C) in September to 41.9°F (5.5°C) by November. Rainfall also dwindles, dropping from 2.48" (63mm) in September to 1.46" (37mm) by November. While daylight hours get compromised, hovering around 11 hours in November, visitors are still able to enjoy a reasonable amount of sunshine.Winter weather in Decorah
Winters in Decorah can be intense. From December to February, temperatures often plunge to a chilly low, with an average high of only 28.4°F (-2°C) in December. Snowfall makes a grand entry in these months, escalating from 4.57" (116mm) in December to as much as 5.98" (152mm) in February. Simultaneously, daylight hours shrink, reducing to a minimum of 9 hours in December. This season is especially noteworthy for the heightened wind speeds up to 10.4mph (16.7km/h) in February.Weather in January
January holds the depths of winter for Decorah, Iowa, with the chill of the season truly taking hold. Residents and visitors alike should prepare for lower temperatures, generally falling from 22.3°F (-5.4°C) to 9.7°F (-12.4°C), as the month progresses. Weather in January »Weather in February
February in Decorah undergoes a slight change as it rises from the chill of January. This ascent is subtle and may go unnoticed to the untrained observer. As winter presses on, periods of snowfall continue to blanket the city, but with a slightly reduced frequency compared to January. Weather in February »Weather in March
The vestiges of winter linger in Decorah's weather in March, though signs of spring slowly make their presence felt. Vitamin D becomes more available as sunlight graces the city for up to 12 hours a day providing more opportunities for outdoor activities. Weather in March »Weather in April
April marks the true onset of spring in Decorah. The landscape gradually trades its wintry white for a myriad of colors as temperatures steadily climb and the ice melts away. The melting ice combines with frequent bouts of rainfall to increase overall humidity. Weather in April »Weather in May
Embracing milder temperatures, the weather in May in Decorah is decidedly more comfortable. The city recovers its lush green appearance as rainfall increases significantly, reaching its peak of 4.06" (103mm) this month. Spring's progress introduces a revival of nature, with days growing longer and landscapes flourishing under the warmer sunlight. Weather in May »Weather in June
As summer settles in, June welcomes the peak of warmth in Decorah. This month, the highest temperatures characterize the weather, reaching up to 75°F (23.9°C), while rainfall continues to occur, although at a reduced rate. More sunlight brightening the day encourages more outdoor activities. Weather in June »Weather in July
As midsummer arrives, July holds the spot as the warmest month in Decorah. Despite the high temperatures now reaching to 78.4°F (25.8°C), relative humidity remains pretty consistent at 84%. Increased day length yields plentiful sunlight, prompting locals and tourists to partake in numerous outdoor activities and events. Weather in July »Weather in August
August brings a slight reduction in temperature, yet the warmth of summer persists in Decorah. Contrary to the norm, the atmospheric pressure increases slightly indicating a superior balance between temperature and humidity. Peak summer comes to an end, signaling the commencement of milder days. Weather in August »Weather in September
September in Decorah marks the onset of Fall, characterized by crisp air and a decrease in average temperatures. Although this transition reduces the length of day to 12.5 hours, bright sunshine still dominates much of the day. Weather in September »Weather in October
October witnesses Decorah fully immersed in the transformative magic of fall. While temperatures continue to drop and snowfall starts again with 0.43" (11mm) on average, fall foliage reaches its peak, surrounding the city with a blanket of vivid colors. Weather in October »Weather in November
As fall shades into winter, November brings a considerable drop in temperatures in Decorah. Despite the decrease, the wintry precipitation is relatively low, with only 2.2" (56mm) of snowfall on average. Shortened daylight hours and increased cloud cover serve as a harbinger of the approaching winter season. Weather in November »Weather in December
December rings in the winter season in Decorah, reverting back to the cold weather conditions experienced at the start of the year. Average snowfall increases to 4.57" (116mm), the second-highest for the year, resulting in a white Christmas for the city. Weather in December »Updated: Feb 12, 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 tends to be the coldest month, with temperatures averaging a daily high of 22.3°F (-5.4°C) and a low of 9.7°F (-12.4°C).
January and February, with an average relative humidity of 89%, are most humid months in Decorah, Iowa.
The month with the least rainfall is January, when the rain falls for 4.5 days and typically collects 1.1" (28mm) of precipitation.
In Decorah, during the entire year, the rain falls for 149 days and collects up to 30.59" (777mm) of precipitation.
January through May, October through December are months with snowfall in Decorah, Iowa.
In Decorah, during the entire year, snow falls for 60.9 days and aggregates up to 24.37" (619mm) of snow.
The month with the least sunshine in Decorah, Iowa, is January, with an average of 3.5h of sunshine.
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 1.
February is the month with the most snowfall in Decorah. Snow falls for 12.8 days and accumulates 5.98" (152mm) of snow.
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.
May through August, with an average maximum UV index of 5, are months with the highest UV index.
June is the month with the most rainfall in Decorah. Rain falls for 20.3 days and accumulates 5.04" (128mm) of precipitation.
In Decorah, Iowa, snow does not fall in June through September.
June has the longest days of the year in Decorah, with an average of 15h and 18min of daylight.
July temperatures in Decorah tend to peak at an average high of 78.4°F (25.8°C) and dip to a low of 61.9°F (16.6°C).
With an average of 9.8h of sunshine, August has the most sunshine of the year in Decorah.
The least humid month in Decorah is October, with an average relative humidity of 76%.
The month with the shortest days in Decorah is December, with an average of 9h and 0min of daylight.
Average temperature
Decorah, IA
The warmest month (with the highest average high temperature) is July (78.4°F).
The month with the lowest average high temperature is January (22.3°F).
The month with the highest average low temperature is July (61.9°F).
The coldest month (with the lowest average low temperature) is January (9.7°F).
Average pressure
Decorah, IA
- Average pressure in January:
30.13"Hg - Average pressure in February:
30.13"Hg - Average pressure in March:
30.08"Hg - Average pressure in April:
29.94"Hg - Average pressure in May:
29.94"Hg - Average pressure in June:
29.89"Hg
- Average pressure in July:
29.96"Hg - Average pressure in August:
29.96"Hg - Average pressure in September:
30.02"Hg - Average pressure in October:
29.99"Hg - Average pressure in November:
30.07"Hg - Average pressure in December:
30.1"Hg
The months with the highest atmospheric pressure are January and February (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed
Decorah, IA
- Average wind speed in January:
10.2mph - Average wind speed in February:
10.1mph - Average wind speed in March:
9.9mph - Average wind speed in April:
10.4mph - Average wind speed in May:
9mph - Average wind speed in June:
7.9mph
- Average wind speed in July:
7.1mph - Average wind speed in August:
7mph - Average wind speed in September:
8.1mph - Average wind speed in October:
9.4mph - Average wind speed in November:
10.1mph - Average wind speed in December:
9.7mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (7mph).
Average humidity
Decorah, IA
The months with the highest relative humidity are January and February (89%).
The month with the lowest relative humidity is October (76%).
Average rainfall
Decorah, IA
- Average rainfall in January:
1.1" - Average rainfall in February:
1.26" - Average rainfall in March:
1.81" - Average rainfall in April:
3.39" - Average rainfall in May:
4.06" - Average rainfall in June:
5.04"
The wettest month (with the highest rainfall) is June (5.04").
The driest month (with the least rainfall) is January (1.1").
Average rainfall days
Decorah, IA
- Average rainfall days in January:
4.5 days - Average rainfall days in February:
4.4 days - Average rainfall days in March:
10.7 days - Average rainfall days in April:
16.5 days - Average rainfall days in May:
20.3 days - Average rainfall days in June:
20.3 days
- Average rainfall days in July:
18 days - Average rainfall days in August:
14.9 days - Average rainfall days in September:
13.3 days - Average rainfall days in October:
11.7 days - Average rainfall days in November:
8 days - Average rainfall days in December:
6.4 days
The months with the highest number of rainy days are May and June (20.3 days).
The month with the least rainy days is February (4.4 days).
Average snowfall
Decorah, IA
- Average snowfall in January:
5.63" - Average snowfall in February:
5.98" - Average snowfall in March:
2.95" - Average snowfall in April:
2.44" - Average snowfall in May:
0.16" - Average snowfall in June:
0"
The month with the highest snowfall is February (5.98").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days
Decorah, IA
- Average snowfall days in January:
14.3 days - Average snowfall days in February:
12.8 days - Average snowfall days in March:
8.8 days - Average snowfall days in April:
3.8 days - Average snowfall days in May:
0.4 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:
1.8 days - Average snowfall days in November:
5.9 days - Average snowfall days in December:
13.1 days
The month with the highest number of snowfall days is January (14.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight / Average sunshine
Decorah, IA
- Average daylight in January:
9h and 24min - Average daylight in February:
10h and 30min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 24min - Average daylight in May:
14h and 42min - Average daylight in June:
15h and 18min
- Average daylight in July:
15h and 0min - Average daylight in August:
13h and 54min - Average daylight in September:
12h and 30min - Average daylight in October:
11h and 0min - Average daylight in November:
9h and 42min - Average daylight in December:
9h and 0min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in January:
3h and 30min - Average sunshine in February:
3h and 42min - Average sunshine in March:
5h and 48min - Average sunshine in April:
7h and 24min - Average sunshine in May:
8h and 12min - Average sunshine in June:
9h and 12min
- Average sunshine in July:
9h and 42min - Average sunshine in August:
9h and 48min - Average sunshine in September:
8h and 54min - Average sunshine in October:
5h and 12min - Average sunshine in November:
5h and 0min - Average sunshine in December:
3h and 54min
The month with the most sunshine is August (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).
Average sunshine days
Decorah, IA
- Average sunshine days in January:
14 days - Average sunshine days in February:
13.3 days - Average sunshine days in March:
13 days - Average sunshine days in April:
10.3 days - Average sunshine days in May:
8.2 days - Average sunshine days in June:
7.1 days
- Average sunshine days in July:
8.6 days - Average sunshine days in August:
12.3 days - Average sunshine days in September:
14.5 days - Average sunshine days in October:
15.6 days - Average sunshine days in November:
16.2 days - Average sunshine days in December:
14.5 days
The month with the most sunshine days is November (16.2 days).
The month with the least sunshine days is June (7.1 days).
Average UV index
Decorah, IA
The months with the highest UV index are May, June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 1).
Average cloud cover
Decorah, IA
The month with the most cloud cover is January (Cloud cover 64).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility
Decorah, IA
The months with the highest visibility are March, April, May, June, August, September, October and November (6mi).
The months with the lowest visibility are January, February, July and December (5mi).
