January Weather in Johnston, United States

Last updated: June 24, 2025

In January, the average temperature in Johnston, United States hovers around 9°C (48°F). Expect a temperature range with a minimum dipping to -8°C (18°F) and a maximum soaring up to 26°C (78°F). During this month, precipitation typically accumulates to 84 mm (3.3 in) over about 9 days, contributing to an average humidity level of 86%.

January Temperature in Johnston

In January in Johnston, the average temperature is 9°C (48°F), with a maximum that can reach 26°C (78°F) and a minimum that can dip as low as -8°C (18°F). Travelers should be prepared for a wide range of temperatures and pack accordingly to ensure comfort during their visit.

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 9°C (48°F), with highs reaching up to 26°C (78°F) and lows dropping to around -8°C (18°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 84 mm (3.3 in) spread over 9 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 84 mm (3.3 inches) of precipitation spread over approximately 9 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 86%. With an average temperature of 9°C (48°F), this humidity feels like a damp chill that wraps around you, making outdoor activities uncomfortable and travel less enjoyable.

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 86%, 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 reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Johnston for better planning.

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 4, 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	9°C (48°F)	84 mm (3.3 inches)	86%	moderate
February Weather	12°C (54°F)	114 mm (4.5 inches)	81%	high
March Weather	14°C (58°F)	85 mm (3.4 inches)	81%	very high
April Weather	18°C (65°F)	115 mm (4.5 inches)	79%	very high
May Weather	23°C (74°F)	110 mm (4.3 inches)	75%	extreme
June Weather	26°C (79°F)	101 mm (4.0 inches)	75%	extreme
July Weather	28°C (82°F)	137 mm (5.4 inches)	80%	extreme
August Weather	27°C (80°F)	142 mm (5.6 inches)	81%	extreme
September Weather	25°C (77°F)	84 mm (3.3 inches)	83%	very high
October Weather	20°C (69°F)	80 mm (3.1 inches)	78%	very high
November Weather	13°C (55°F)	69 mm (2.7 inches)	85%	high
December Weather	10°C (51°F)	119 mm (4.7 inches)	87%	moderate