Contents
- Weather in January
- Frequently asked questions
- Average temperature in January
- Average pressure in January
- Average wind speed in January
- Average humidity in January
- Average rainfall in January
- Average rainfall days in January
- Average snowfall in January
- Average snowfall days in January
- Average daylight in January
- Average sunshine in January
- Average sunshine days in January
- Average UV index in January
- Average cloud cover in January
- Average visibility in January
Weather in January
Temperature
Temperature records in Johnston mark January as the coldest month, with highs averaging 27.9°F (-2.3°C) and lows at 14.4°F (-9.8°C).Humidity
The most humid month in Johnston, Iowa, is January, with an average relative humidity of 83%.Rainfall
The month with the least rainfall in Johnston, Iowa, is January, when the rain falls for 3.8 days and typically collects 0.47" (12mm) of precipitation.Snowfall
Months with snowfall in Johnston are January through May, October through December. January is the month with the most snowfall. Snow falls for 8.4 days and accumulates 2.2" (56mm) of snow.Daylight
In Johnston, the average length of the day in January is 9h and 34min.On the first day of January, sunrise is at 7:41 am and sunset at 4:54 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 5:28 pm CST.
Sunshine
With an average of 4.3h of sunshine, January has the least sunshine of the year.UV index
The month with the lowest UV index is January, with an average maximum UV index of 1. A UV Index reading of 2, and below, represents a minimal health vulnerability from unsafe exposure to UV radiation for the average person.Note: In January, the UV index of 1 transforms into the following advice:
Infants, children, and people with sensitive skin should always have protection against lengthy periods of sun exposure. UV radiation is strongest from the Sun during midday; protect yourself by staying in shaded areas. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
Frequently asked questions
What is the coldest month in Johnston?
How cold is it in Johnston in January?
What is the most humid month in Johnston?
What is the average humidity in January in Johnston?
What is the driest month in Johnston?
How many days does it rain in January in Johnston?
When does it snow the most in Johnston?
How much does it snow in Johnston in January?
How many hours of daylight does Johnston have in January?
When is the sunrise / sunset in January in Johnston?
What is the month with the least sunshine in Johnston?
How many hours of sunshine does Johnston have in January?
When is the lowest UV index in Johnston?
How high is the UV index in January in Johnston?
Average temperature in January
Johnston, IA
- Average high temperature in January: 27.9°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 January: 14.4°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 January
Johnston, IA
- Average pressure in January: 30.16"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 January
Johnston, IA
- Average wind speed in January: 10.3mph
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 January
Johnston, IA
- Average humidity in January: 83%
The month with the highest relative humidity is January (83%).
The month with the lowest relative humidity is October (70%).
Average rainfall in January
Johnston, IA
- Average rainfall in January: 0.47"
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 January
Johnston, IA
- Average rainfall days in January: 3.8 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 January
Johnston, IA
- Average snowfall in January: 2.2"
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 January
Johnston, IA
- Average snowfall days in January: 8.4 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 January /
Average sunshine in January
Johnston, IA
- Average daylight in January: 9h and 4min
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 January: 4h 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 January
Johnston, IA
- Average sunshine days in January: 20.6 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 January
Johnston, IA
- Average UV index in January: 1
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 January
Johnston, IA
- Average cloud cover in January: 53
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 January
Johnston, IA
- Average visibility in January: 6mi
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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