May weather forecast
Grafton, IA

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Weather in May

The last month of the spring, May, is an enjoyable month in Grafton, Iowa, with an average temperature ranging between max 66.6°F (19.2°C) and min 50.4°F (10.2°C).

Temperature

In Grafton, stepping into May brings a temperature increase, moving up from April's fresh 54.3°F (12.4°C) to a refreshing 66.6°F (19.2°C). During May, Grafton's temperature falls to a steady low-temperature average of 50.4°F (10.2°C).

Humidity

In May, the average relative humidity is 74%.

Rainfall

In May, the rain falls for 17.2 days. Throughout May, 3.07" (78mm) of precipitation is accumulated. Throughout the year, there are 134.3 rainfall days, and 25.08" (637mm) of precipitation is accumulated.

Snowfall

Months with snowfall in Grafton are January through May, October through December. May is the last month it regularly snows. During 0.3 snowfall days, in May, Grafton aggregates 0.47" (12mm) of snow. In Grafton, during the entire year, snow falls for 57 days and aggregates up to 22.83" (580mm) of snow.

Daylight

The average length of the day in May is 14h and 43min.
On the first day of the month, sunrise is at 6:04 am and sunset at 8:14 pm. On the last day of May, sunrise is at 5:34 am and sunset at 8:45 pm CDT.

Sunshine

The average sunshine in May in Grafton, Iowa, is 8.4h.

UV index

The average daily maximum UV index in May is 5. A UV Index estimate of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: The maximum UV index, 5 during May, leads to the following recommendations:
Undertake precautions - It is suggested to shield oneself from sunburn. Solar radiation peaks around mid-day, so it's wise to limit exposure to the Sun at this time. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear. Be alert! Nearly double the UV rays from the Sun can be reflected by snow.
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Frequently asked questions

What are the temperatures in Grafton in May?

In Grafton, in May, the average high-temperature is 66.6°F (19.2°C), and the average low-temperature is 50.4°F (10.2°C).

What is the average humidity in May in Grafton?

The average relative humidity in May in Grafton, Iowa, is 74%.

How many days does it rain in May in Grafton?

In Grafton, Iowa, in May, it is raining for 17.2 days, with typically 3.07" (78mm) of accumulated precipitation.

What is the last month it snows in Grafton?

May is the last month it regularly snows in Grafton, Iowa. During 0.3 snowfall days, in May, Grafton aggregates 0.47" (12mm) of snow.

What is the average length of the day in May in Grafton?

The average day length in May in Grafton is 14h and 43min.

When are sunrise and sunset in May in Grafton?

In May, on the first day of the month, sunrise is at 6:04 am and sunset at 8:14 pm. On the last day of the month, in Grafton, Iowa, sunrise is at 5:34 am and sunset at 8:45 pm CDT.

How long on average sun shines in May in Grafton?

The average sunshine duration in May in Grafton, Iowa, is 8.4h.

What is the UV index reading in May in Grafton?

In May, the average daily maximum UV index in Grafton is 5. A UV Index reading of 3 to 5 represents a medium health risk from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Grafton, IA

Average temperature in May - Grafton, IA
  • Average high temperature in May: 66.6°F

The warmest month (with the highest average high temperature) is July (79.2°F).
The month with the lowest average high temperature is January (21.6°F).

  • Average low temperature in May: 50.4°F

The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (9°F).

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Average pressure in May
Grafton, IA

Average pressure in May - Grafton, IA
  • Average pressure in May: 29.93"Hg

The months with the highest atmospheric pressure are January and February (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).

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Average wind speed in May
Grafton, IA

Average wind speed in May - Grafton, IA
  • Average wind speed in May: 9.4mph

The windiest month (with the highest average wind speed) is April (10.8mph).
The calmest months (with the lowest average wind speed) are July and August (7.4mph).

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Average humidity in May
Grafton, IA

Average humidity in May - Grafton, IA
  • Average humidity in May: 74%

The month with the highest relative humidity is January (90%).
The months with the lowest relative humidity are April and October (72%).

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Average rainfall in May
Grafton, IA

Average rainfall in May - Grafton, IA
  • Average rainfall in May: 3.07"

The wettest month (with the highest rainfall) is June (4.13").
The driest month (with the least rainfall) is January (0.94").

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Average rainfall days in May
Grafton, IA

Average rainfall days in May - Grafton, IA
  • Average rainfall days in May: 17.2 days

The month with the highest number of rainy days is June (18.4 days).
The month with the least rainy days is February (2.9 days).

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Average snowfall in May
Grafton, IA

Average snowfall in May - Grafton, IA
  • Average snowfall in May: 0.47"

The month with the highest snowfall is February (5.94").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in May
Grafton, IA

Average snowfall days in May - Grafton, IA
  • Average snowfall days in May: 0.3 days

The month with the highest number of snowfall days is January (13.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in May /
Average sunshine in May
Grafton, IA

Average daylight in May / Average sunshine in May - Grafton, IA
  • Average daylight in May: 14h and 4min

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 May: 8h and 2min

The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 24min).

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Average sunshine days in May
Grafton, IA

Average sunshine days in May - Grafton, IA
  • Average sunshine days in May: 11.7 days

The month with the most sunshine days is October (18.1 days).
The month with the least sunshine days is June (9.1 days).

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Average UV index in May
Grafton, IA

Average UV index in May - Grafton, IA
  • Average UV index in May: 5

The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 1).

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Average cloud cover in May
Grafton, IA

Average cloud cover in May - Grafton, IA
  • Average cloud cover in May: 44

The month with the most cloud cover is January (Cloud cover 65).
The month with the least cloud cover is August (Cloud cover 32).

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Average visibility in May
Grafton, IA

Average visibility in May - Grafton, IA
  • Average visibility in May: 6mi

The months with the highest visibility are March, April, May, June, September, October and November (6mi).
The months with the lowest visibility are January, February, July, August and December (5mi).

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Grafton, Iowa, USA

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