Contents
- Weather in July
- Frequently asked questions
- Average temperature in July
- Average pressure in July
- Average wind speed in July
- Average humidity in July
- Average rainfall in July
- Average rainfall days in July
- Average snowfall in July
- Average snowfall days in July
- Average daylight in July
- Average sunshine in July
- Average sunshine days in July
- Average UV index in July
- Average cloud cover in July
- Average visibility in July
Weather in July
Temperature
July tends to be the warmest month in Johnston, with temperatures averaging a daily high of 82.4°F (28°C) and a low of 65.1°F (18.4°C).Heat index
The heat index for July is estimated at a tropical 89.6°F (32°C). Prolonged exposure combined with continuous activity could lead to exhaustion, and possibly heat cramps.Be advised, the heat index considers values for conditions in shade and with a light breeze. Heat index values might soar by up to 15 Fahrenheit (8 Celsius) degrees with exposure to direct sunshine.
Note: The heat index, also known as 'real feel' or 'feels like', measures the perceived warmth when incorporating the humidity present in the air. The effect is experienced differently by individuals, hinging on unique characteristics such as body mass, stature, and level of activity. Consider the sun's direct rays and their impact; they can potentially increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are quite important for babies and toddlers. Young kids are often more at risk than adults as they tend to perspire less. Besides, their skin surface is larger relative to their small bodies, and their increased heat output from their active lifestyle compounds their risk.
Humidity
In Johnston, the average relative humidity in July is 81%.Rainfall
In July, the rain falls for 12.8 days. Throughout July, 1.42" (36mm) of precipitation is accumulated. In Johnston, during the entire year, the rain falls for 114.6 days and collects up to 15.51" (394mm) of precipitation.Snowfall
June through September are months without snowfall.Daylight
In July, the average length of the day is 14h and 50min.On the first day of the month, sunrise is at 5:44 am and sunset at 8:53 pm. On the last day of July, sunrise is at 6:09 am and sunset at 8:33 pm CDT.
Sunshine
With an average of 10.4h of sunshine, July has the most sunshine of the year in Johnston.UV index
The months with the highest UV index in Johnston, Iowa, are June and July, with an average maximum UV index of 6. A UV Index estimate of 6 to 7 represents a high health hazard from unsafe exposure to UV radiation for the ordinary person.Note: An average maximum UV index of 6 in July leads to these recommendations:
Conform to measures and uphold sun safety traditions. Warding off skin and eye harm is necessary. Limit direct sun exposure and seek shade between 10 a.m. and 4 p.m., the time of the most intense UV radiation, noting that shade structures may not provide total sun protection. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.
Frequently asked questions
What part of the year is the hottest in Johnston?
How hot does it get in Johnston in July?
What is the average humidity in July in Johnston?
How much does it rain in Johnston in July?
When it does not snow in Johnston?
What is the average length of the day in July in Johnston?
What time are sunrise and sunset in July in Johnston?
What month has the most sunshine in Johnston?
How many hours of sunshine does Johnston have in July?
When is the highest UV index in Johnston?
How high is the UV index in July in Johnston?
Average temperature in July
Johnston, IA
- Average high temperature in July: 82.4°F
The warmest month (with the highest average high temperature) is July (82.4°F).
The month with the lowest average high temperature is January (27.9°F).
- Average low temperature in July: 65.1°F
The month with the highest average low temperature is July (65.1°F).
The coldest month (with the lowest average low temperature) is January (14.4°F).
Average pressure in July
Johnston, IA
- Average pressure in July: 29.96"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in July
Johnston, IA
- Average wind speed in July: 7mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (7mph).
Average humidity in July
Johnston, IA
- Average humidity in July: 81%
The month with the highest relative humidity is January (83%).
The month with the lowest relative humidity is October (70%).
Average rainfall in July
Johnston, IA
- Average rainfall in July: 1.42"
The wettest months (with the highest rainfall) are May and June (2.52").
The driest month (with the least rainfall) is January (0.47").
Average rainfall days in July
Johnston, IA
- Average rainfall days in July: 12.8 days
The month with the highest number of rainy days is May (16.3 days).
The month with the least rainy days is February (3.5 days).
Average snowfall in July
Johnston, IA
- Average snowfall in July: 0"
The month with the highest snowfall is January (2.2").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in July
Johnston, IA
- Average snowfall days in July: 0 days
The month with the highest number of snowfall days is January (8.4 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in July /
Average sunshine in July
Johnston, IA
- Average daylight in July: 14h and 5min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in July: 10h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).
Average sunshine days in July
Johnston, IA
- Average sunshine days in July: 14.8 days
The month with the most sunshine days is December (22.8 days).
The month with the least sunshine days is June (11.2 days).
Average UV index in July
Johnston, IA
- Average UV index in July: 6
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in July
Johnston, IA
- Average cloud cover in July: 29
The month with the most cloud cover is January (Cloud cover 53).
The month with the least cloud cover is September (Cloud cover 28).
Average visibility in July
Johnston, IA
- Average visibility in July: 5mi
The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).
Johnston, Iowa, USA
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