Climate and monthly weather forecast
Challis, ID

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The climate of Challis

In Challis, Idaho, the predominant climate is classified as Dfb according to the Köppen system. This refers to a Humid Continental climate that experiences no dry season, with warm summers. Geographically nestled in the mountainous region of central Idaho, Challis is subject to a distinct range of weather conditions throughout the year.

Temperatures over the year fluctuate significantly. The monthly average highs range from 28.4°F (-2°C) in January to a peak of 76.6°F (24.8°C) in July. Conversely, the monthly lows show a similar variation, reaching a minimum of 8.1°F (-13.3°C) in January and climbing to a balmy 47.8°F (8.8°C) in August. Humidity levels generally follow an opposite trend with respect to the temperature, starting at 86% in January, and decreasing to the yearly minimum of 38% during July and August, before climbing back up towards the end of the year.

In terms of precipitation, Challis experiences both rainfall and snowfall. Rainfall is relatively evenly distributed throughout the year, varying from 0.28" (7mm) during the driest month in July to 1.1" (28mm) during the wettest month in June. Snowfall, on the other hand, is common from October to April with peak snowfall of 3.54" (90mm) occurring in February.

The best time to visit Challis

The best time to visit Challis primarily depends upon what one prefers in terms of weather conditions. For those who relish warmer temperatures and less humidity, July seems an ideal time. July offers the highest temperatures with an average high of 76.6°F (24.8°C) and the lowest relative humidity levels at 38%. This month also brings the least amount of rainfall, which facilitates outdoor activities. Moreover, daylight is at its maximum, with 15.2 hours of daylight per day, that invigorates longer exploration durations.

The worst time to visit Challis

Visitors not fond of lower temperatures and significant snowfall should consider avoiding winter months, particularly January. January averages the lowest temperatures with highs of 28.4°F (-2°C) and lows dipping down to 8.1°F (-13.3°C). January also receives a considerable amount of snowfall with 3.23" (82mm) on average and shorter daylight duration, limiting outdoor activities.

Spring weather in Challis

Spring in Challis is marked by a gradual warming trend from the winter. During this season, March to May, temperatures show an upward movement from an average high of 35.2°F (1.8°C) during March to 54.5°F (12.5°C) in May. Nighttime lows also rise from 18°F (-7.8°C) to 33.4°F (0.8°C) in the same period. The spring witnesses a drop in humidity levels from 82% in March to 61% in May. The amount of rainfall in this season increases slightly from 0.55" (14mm) in March to 0.59" (15mm) in May.

Summer weather in Challis

Summer, from June to August, brings the highest temperatures in Challis. Average highs swing from 65.8°F (18.8°C) in June to a peak of 76.6°F (24.8°C) in July, before slightly dropping to 75.4°F (24.1°C) in August. Average lows also rise, registering between 40.3°F (4.6°C) to 47.8°F (8.8°C) in these three months. The humidity levels drop significantly, reaching the lowest yearly levels of 38% in July and August. Summer features a surge in rainfall, peaking at 1.1" (28mm) in June, and then drops to 0.31" (8mm) by August.

Autumn weather in Challis

Autumn, encompassing September through November, sees Challis transitioning towards colder temperatures. In this season, the average high drops from 65.7°F (18.7°C) in September to 36.7°F (2.6°C) in November. Similarly, average lows descend from 41.5°F (5.3°C) to 18.9°F (-7.3°C). Humidity begins to rise from 45% in September to 75% in November. The rainfall flutters around 0.5" (13mm) in September and November, with a slightly increased 0.55" (14mm) in October.

Winter weather in Challis

Winter weather in Challis, from December to February, is characterized by low temperatures and abundant snowfall. Average highs range from 28.4°F (-2°C) in January to 35.2°F (1.8°C) in February. The average lows are between 8.1°F (-13.3°C) to 18°F (-7.8°C) in these months. The humidity levels are highest during these months, skyrocketing up to 87% in February. Rainfall stays below 0.6" (15mm), but snowfall picks up substantially, reaching a peak of 3.54" (90mm) in February.

Weather in January

In Challis, Idaho, winter persists in January with the coldest temperatures registered. The low temperatures of this month drop to 8.1°F (-13.3°C), making it one of the coldest months. The weather is characterized by a high possibility of snow with frequent snowfall, making it the ideal setting for winter activities. Weather in January »

Weather in February

February in Challis maintains the winter conditions seen in January, but with a subtle increase in temperature. The gradual transition from winter to spring is characterized by short-lived snowfalls. February sees the heaviest snowfall of the year, with accumulations reaching 3.54" (90mm). Weather in February »

Weather in March

March exhibits definite signs of change in weather, shifting from the cold grip of winter towards the mildness of spring. The shift is characterized by a decrease in snowfall and a relative increase in rainfall, making it the month with the highest number of rainfall days, 7.4 on average. Weather in March »

Weather in April

As spring unfolds in Challis in April, warmth engulfs the city and the frosty weather of winter becomes a memory. The rains continue in April and combined with warmer temperatures, contribute to the blooming of flora across Challis. Weather in April »

Weather in May

In May, Challis experiences a steady climb in temperatures, likely to be the beginning of the summer season. The rainfall quantity drops and is replaced by more hours of sunshine, making it a leisurely period for outdoor activities. Weather in May »

Weather in June

June represents the onset of the peak summer period in Challis, with temperatures reaching their zenith and rainfall occurrence becoming scant. The soaring temperatures, which can go up to an average high of 65.8°F (18.8°C), coupled with open skies, create the perfect summer setting. Weather in June »

Weather in July

July is the summit of the summer season in Challis, where days are hot under clear and sunny skies. This month records the warmest temperatures of the year with an average high at 76.6°F (24.8°C). The weather conditions are dry with exceptionally low humidity levels and minimal clouds. Weather in July »

Weather in August

August in Challis continues the summer spell with no significant changes in temperature or weather patterns from July. The average high temperature remains consistent at 75.4°F (24.1°C). Though the rainfall quantity is minimal, it occurs more frequently than in the previous month. Weather in August »

Weather in September

The swing towards fall begins in September in Challis with a remarkable drop in temperature and increased cloud cover. The average high temperature falls to 65.7°F (18.7°C), indicating the change from the heat of summer to the coolness of autumn. Weather in September »

Weather in October

October ensures the full arrival of fall in Challis with a further decrease in temperature and the dominance of rainfall over snowfall. The coolness sets across the city as temperatures plummet, providing relief from the scorching summer heat. Weather in October »

Weather in November

Come November, Challis makes a swift shift from fall to winter. The onset of winter is evident as both the days get shorter and the average high temperature drops to 36.7°F (2.6°C). Rainfall decreases however, snowfall begins to occur, albeit not as intensely as in the ensuing winter months. Weather in November »

Weather in December

December serves as the mid-point of the winter season in Challis, with a firm grip of cold weather conditions. Temperature continues to drop, reaching a low of 8.6°F (-13°C) in this month. Challis experiences an increase in snowfall with levels reaching 3.03" (77mm). Weather in December »
Updated: Aug 27, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How many days does it rain?

Throughout the year, there are 75.7 rainfall days, and 6.38" (162mm) of precipitation is accumulated.

When does it snow?

January through June, September through December are months with snowfall.

How many days does it snow?

Throughout the year, in Challis, there are 51.7 snowfall days, and 18.62" (473mm) of snow is accumulated.

What is the month with the least sunshine?

January has the least sunshine of the year, with an average of 5.8h of sunshine.

When is the lowest UV index?

January through April, October through December, with an average maximum UV index of 2, are months with the lowest UV index.

What is the most humid month?

With an average relative humidity of 87%, February is the most humid month.

What is the snowiest month?

February is the month with the most snowfall. Snow falls for 9.4 days and accumulates 3.54" (90mm) of snow.

When is Daylight Saving Time (DST)?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from MST to MDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from MDT to MST.

What is the wettest month?

June is the month with the most rainfall. Rain falls for 10.2 days and accumulates 1.1" (28mm) of precipitation.

When are the longest days?

June has the longest days of the year, with an average of 15h and 30min of daylight.

What are the months with the highest UV index?

June and July, with an average maximum UV index of 5, are months with the highest UV index.

What part of the year is the hottest?

July is Challis's warmest month, registering average high temperatures of 76.6°F (24.8°C) and lows of 47.3°F (8.5°C).

What is the least humid month?

July and August, with an average relative humidity of 38%, are the least humid months.

What is the driest month?

July is the month with the least rainfall. Rain falls for 4.7 days and accumulates 0.28" (7mm) of precipitation.

When it does not snow in Challis?

July and August are months without snowfall.

What month has the most sunshine?

July has the most sunshine of the year, with an average of 11.9h of sunshine.

What month is the coldest?

During the coldest month in Challis, December, temperatures average a high of 26.1°F (-3.3°C) and a low of 8.6°F (-13°C).

What is the month with the shortest days?

With an average of 8h and 54min of daylight, December has the shortest days of the year.

Average temperature
Challis, ID

Average temperature - Challis, ID

The warmest month (with the highest average high temperature) is July (76.6°F).
The month with the lowest average high temperature is December (26.1°F).

The month with the highest average low temperature is August (47.8°F).
The coldest month (with the lowest average low temperature) is January (8.1°F).

Average pressure
Challis, ID

Average pressure - Challis, ID

The month with the highest atmospheric pressure is January (30.27"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed
Challis, ID

Average wind speed - Challis, ID

The windiest months (with the highest average wind speed) are June and July (5.7mph).
The calmest month (with the lowest average wind speed) is January (4.8mph).

Average humidity
Challis, ID

Average humidity - Challis, ID

The month with the highest relative humidity is February (87%).
The months with the lowest relative humidity are July and August (38%).

Average rainfall
Challis, ID

Average rainfall - Challis, ID

The wettest month (with the highest rainfall) is June (1.1").
The driest month (with the least rainfall) is July (0.28").

Average rainfall days
Challis, ID

Average rainfall days - Challis, ID

The month with the highest number of rainy days is June (10.2 days).
The month with the least rainy days is January (3.8 days).

Average snowfall
Challis, ID

Average snowfall - Challis, ID

The month with the highest snowfall is February (3.54").
The months with the least snowfall are July and August (0").

Average snowfall days
Challis, ID

Average snowfall days - Challis, ID

The month with the highest number of snowfall days is December (10.1 days).
The months with the least snowfall days are July and August (0 days).

Average daylight / Average sunshine
Challis, ID

Average daylight / Average sunshine - Challis, ID

The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).

The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 5h and 48min).

Average sunshine days
Challis, ID

Average sunshine days - Challis, ID

The month with the most sunshine days is July (24.1 days).
The months with the least sunshine days are March and April (17.2 days).

Average UV index
Challis, ID

Average UV index - Challis, ID

The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 2).

Average visibility
Challis, ID

Average visibility - Challis, ID

The months with the highest visibility are April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and February (4mi).

Challis, Idaho, USA

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