Contents
- Weather in May
- Frequently asked questions
- Average temperature in May
- Average pressure in May
- Average wind speed in May
- Average humidity in May
- Average rainfall in May
- Average rainfall days in May
- Average snowfall in May
- Average snowfall days in May
- Average daylight in May
- Average sunshine in May
- Average sunshine days in May
- Average UV index in May
- Average cloud cover in May
- Average visibility in May
Weather in May
Temperature
As Johnston, South Carolina, transitions into May, a marginal rise in the average high-temperature is observed, moving from 73.9°F (23.3°C) in April to a still warm 81.1°F (27.3°C). Throughout May, the temperature tends to fall to a consistent average low of 62.2°F (16.8°C).Heat index
May's mean heat index is computed to be a tropical 86°F (30°C). Continuous exposure and activity could induce a sense of tiredness and subsequently, heat cramps.Thinking about the heat index, one should account for its values in shaded areas with gentle breezes. Direct sunlight exposure may result in a rise of the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'real feel', is derived by integrating air temperature with the existing relative humidity to express the perceived warmth. Factors including metabolic differences, physical activity, and clothing are additional elements that influence the individual's temperature experience. One's exposure to direct sunlight has the potential to intensify the heat sensation, increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values remain especially vital for babies and toddlers. Kids are usually in more danger than grown-ups as they tend to sweat less. Plus, their bigger skin surface in relation to their small frames and increased heat generation due to their activity level make them more susceptible.
Humidity
The average relative humidity in May in Johnston is 74%.Rainfall
In Johnston, during May, the rain falls for 14.8 days and regularly aggregates up to 2.8" (71mm) of precipitation. Throughout the year, there are 149.8 rainfall days, and 28.58" (726mm) of precipitation is accumulated.Snowfall
April through November are months without snowfall in Johnston.Daylight
In May, the average length of the day in Johnston is 13h and 56min.On the first day of May, sunrise is at 6:37 am and sunset at 8:11 pm. On the last day of the month, sunrise is at 6:17 am and sunset at 8:32 pm EDT.
Sunshine
In Johnston, the average sunshine in May is 10h.UV index
The average daily maximum UV index in May in Johnston is 6. A UV Index reading of 6 to 7 represents a high health risk from exposure to the Sun's UV rays for the ordinary person.Note: During May, 6 as the daily maximum UV index converts into the following advice:
Use protective steps and abide by sun safety guidelines. Safeguarding against skin and eye harm is necessary. The time between 10 a.m. and 4 p.m. is when UV radiation is at its peak. Limit exposure to direct sunlight during these hours. Stay sun-safe with clothing that is both closely woven and worn loosely.
Frequently asked questions
What is the average May temperature in Johnston?
What is the average humidity in May in Johnston?
How much does it rain in Johnston in May?
When it does not snow in Johnston?
How many hours of daylight does Johnston have in May?
When are sunrise and sunset in May in Johnston?
How many hours of sunshine does Johnston have in May?
What is the UV index intensity in May in Johnston?
Average temperature in May
Johnston, SC
- Average high temperature in May: 81.1°F
The warmest month (with the highest average high temperature) is July (91.4°F).
The month with the lowest average high temperature is January (52.7°F).
- Average low temperature in May: 62.2°F
The month with the highest average low temperature is July (72.5°F).
The coldest month (with the lowest average low temperature) is January (36.9°F).
Average pressure in May
Johnston, SC
- Average pressure in May: 30.03"Hg
The months with the highest atmospheric pressure are January, November and December (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.98"Hg).
Average wind speed in May
Johnston, SC
- Average wind speed in May: 6.7mph
The windiest months (with the highest average wind speed) are February and April (8.1mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).
Average humidity in May
Johnston, SC
- Average humidity in May: 74%
The month with the highest relative humidity is December (76%).
The month with the lowest relative humidity is July (70%).
Average rainfall in May
Johnston, SC
- Average rainfall in May: 2.8"
The wettest month (with the highest rainfall) is December (3.03").
The driest month (with the least rainfall) is September (1.42").
Average rainfall days in May
Johnston, SC
- Average rainfall days in May: 14.8 days
The month with the highest number of rainy days is July (17.5 days).
The month with the least rainy days is November (7.8 days).
Average snowfall in May
Johnston, SC
- Average snowfall in May: 0"
The month with the highest snowfall is February (0.59").
The months with the least snowfall are April, May, June, July, August, September, October and November (0").
Average snowfall days in May
Johnston, SC
- Average snowfall days in May: 0 days
The months with the highest number of snowfall days are January and February (0.4 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in May /
Average sunshine in May
Johnston, SC
- Average daylight in May: 13h and 5min
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).
- Average sunshine in May: 10h and 0min
The months with the most sunshine are June and July (Average sunshine: 10h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 24min).
Average sunshine days in May
Johnston, SC
- Average sunshine days in May: 14.7 days
The month with the most sunshine days is October (21.8 days).
The month with the least sunshine days is July (11.2 days).
Average UV index in May
Johnston, SC
- Average UV index in May: 6
The months with the highest UV index are June, July and August (UV index 7).
The month with the lowest UV index is January (UV index 2).
Average cloud cover in May
Johnston, SC
- Average cloud cover in May: 33
The month with the most cloud cover is December (Cloud cover 41).
The month with the least cloud cover is October (Cloud cover 27).
Average visibility in May
Johnston, SC
- Average visibility in May: 6mi
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).
Johnston, South Carolina, USA
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