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
With average high temperatures of 82.4°F (28°C) and lows of 65.1°F (18.4°C), July is the warmest month in Johnston.Heat index
In July, the heat index is appraised at a tropical 89.6°F (32°C). Enduring exposure and continuous activity might cause a feeling of tiredness and induce heat cramps.Note that heat index values are valued for light wind and location in the shade. Exposure to unobstructed sunshine could lead to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'real feel', binds temperature metrics with humidity values to give a sense of the actual warmth. Factors encompassing physical activity, clothing, and metabolic differences have a role in shaping the individual's impression of temperature. Taking into account that direct sunlight can boost the heat effect, the heat index may rise by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial 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
In July, the average relative humidity in Johnston is 81%.Rainfall
In Johnston, during July, the rain falls for 12.8 days and regularly aggregates up to 1.42" (36mm) of precipitation. Throughout the year, there are 114.6 rainfall days, and 15.51" (394mm) of precipitation is accumulated.Snowfall
In Johnston, snow does not fall in June through September.Daylight
The average length of the day in July 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.UV index
The months with the highest UV index are June and July, with an average maximum UV index of 6. A UV Index estimate of 6 to 7 represents a high threat to health from exposure to the Sun's UV radiation for the ordinary person.Note: The UV index of 6 in July translates into these instructions:
Adhere to precautions and respect sun safety doctrines. Avoiding sunburn is vital. Avoid direct exposure to the Sun between 10 a.m. and 4 p.m., the peak period for UV radiation, noting that objects like parasols or canopies might not offer complete sun protection. Opt for tightly woven and loose clothing to enhance protection from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the hottest time of year?
How hot is it in July?
What is the average humidity in July?
How many days does it rain in July?
When it does not snow?
How many hours of daylight does Johnston have in July?
What time are sunrise and sunset in July in Johnston?
What month has the most sunshine?
How long on average sun shines in July in Johnston?
When is the highest UV index?
What is the UV index reading in July?
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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