January Weather in Johnston, United States

Last updated: June 24, 2025

In January, the average temperature in Johnston, United States hovers around -6°C (22°F), with potential extremes ranging from a minimum of -31°C (-23°F) to a maximum of 14°C (57°F). Expect 37 mm (1.4 in) of precipitation spread over 6 days, accompanied by a notable average humidity of 78%. Bundle up and stay dry!

January Temperature in Johnston

In January in Johnston, the average temperature is -6°C (22°F). Maximums can reach 14°C (57°F), while minimums can plummet to as low as -31°C (-23°F). Travelers should be well-prepared for a wide range of temperatures and dress accordingly.

January Weather in Johnston: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in Johnston, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Johnston, January typically has an average temperature of -6°C (22°F), with highs reaching up to 14°C (57°F) and lows dropping to around -31°C (-23°F).

Data source: Temperature data for Johnston generated using information from the Copernicus Climate Change Service.

January Precipitation in Johnston

In Johnston in January, the precipitation amount is 37 mm (1.4 in) over a span of 6 days.

January Precipitation Trends in Johnston

The chart displays monthly precipitation patterns in Johnston, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Johnston, January typically receives around 37 mm (1.4 inches) of precipitation spread over approximately 6 days.

Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

January Humidity in Johnston

In Johnston in January, humidity is 78%. With an average temperature of -6°C (22°F), this humidity feels like a biting chill that seeps through your layers, making outdoor activities less enjoyable and creating a sharp contrast that can be unexpectedly uncomfortable for travelers.

January Average Humidity in Johnston

This chart illustrates the average monthly humidity levels in Johnston, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in Johnston is approximately 78%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in Johnston

In Johnston in January, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Johnston, you can check the information here.

Maximum UV Index Levels in Johnston for January

The chart shows the monthly maximum UV Index (UVI) for Johnston in January, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In January, the maximum UV index in Johnston typically reaches 3, which falls under the moderate exposure category.

Data source: Johnston January UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How January Weather in Johnston Compares to Other Months

Weather in Johnston varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Johnston, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Johnston, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-6°C (22°F)	37 mm (1.4 inches)	78%	moderate
February Weather	-5°C (23°F)	40 mm (1.6 inches)	80%	moderate
March Weather	4°C (40°F)	81 mm (3.2 inches)	77%	high
April Weather	9°C (49°F)	75 mm (2.9 inches)	77%	very high
May Weather	17°C (62°F)	169 mm (6.7 inches)	77%	very high
June Weather	23°C (74°F)	109 mm (4.3 inches)	81%	extreme
July Weather	25°C (77°F)	76 mm (3.0 inches)	81%	very high
August Weather	23°C (74°F)	87 mm (3.4 inches)	77%	very high
September Weather	20°C (69°F)	120 mm (4.7 inches)	73%	very high
October Weather	11°C (53°F)	128 mm (5.0 inches)	75%	high
November Weather	3°C (39°F)	39 mm (1.5 inches)	85%	moderate
December Weather	-1°C (31°F)	37 mm (1.5 inches)	83%	moderate