August weather forecast
Johnstown, CO

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Weather in August

In August, the high temperatures persist, though slightly reduced, dropping to 88°F (31.1°C). Despite the distinctive summer feel, a subtle shift in weather patterns hints at the approaching autumn. Johnstown experiences less rainfall, and sunny days keep the summer vibes alive. It's an opportune time to enjoy water activities at the reservoir or a relaxing evening walk along the nature trails.

Temperature

Shifting into August, Johnstown records an average high-temperature of a still hot 88°F (31.1°C), presenting minor fluctuations compared to the previous month. Johnstown experiences a significant downturn from peak daytime temperatures throughout August, with the average low-temperature dipping to a moderate 59°F (15°C).

Heat index

The heat index for August is calculated to be a tropical 87.8°F (31°C). Prolonged activity during exposure might result in a state of fatigue and cause heat cramps.
Know that the heat index computations account for shaded terrains and slight winds. When under direct sunshine, the heat index may be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'real feel', is what the temperature feels like to the human body when the air temperature is combined with the relative humidity. The impact of weather on an individual can be subjective, affected by the person's activity and heat perception, which can vary due to elements including wind, clothing, and metabolic differences. Given direct exposure to sunlight, one might experience a rise in the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are largely significant for babies and toddlers. In general, children are more at risk than adults because they sweat less. Furthermore, the large skin surface compared to their small bodies and the high heat production due to their actions contribute to this vulnerability.

Humidity

August and September, with an average relative humidity of 42%, are the least humid months.

Rainfall

In Johnstown, in August, it is raining for 10.9 days, with typically 0.87" (22mm) of accumulated precipitation. Throughout the year, there are 107.4 rainfall days, and 11.3" (287mm) of precipitation is accumulated.

Snowfall

June through September are months without snowfall.

Daylight

In August, the average length of the day in Johnstown is 13h and 43min.
On the first day of the month, sunrise is at 5:58 am and sunset at 8:13 pm. On the last day of August, sunrise is at 6:26 am and sunset at 7:32 pm MDT.

Sunshine

In August, the average sunshine in Johnstown is 11.8h.

UV index

The months with the highest UV index in Johnstown are June through August, with an average maximum UV index of 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from unsafe exposure to UV radiation for the ordinary person.
Note: The daily high UV index of 6 in August translates into this advice:
Endorse precautions and be consistent with sun safety guidelines. Preventing sunburn is paramount. Stay in the shade and limit direct sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its strongest. Remember, however, that not all shade structures provide full sun protection. Opt for tightly woven and loose clothing to enhance protection from the Sun.
Updated: Feb 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Is it hot in Johnstown during August?

In August, the average high-temperature and low-temperature in Johnstown are 88°F (31.1°C) and 59°F (15°C) respectively. In August, the average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which combines relative humidity and air temperature, is calculated to be 87.8°F (31°C).

What is the least humid month in Johnstown?

August and September, with an average relative humidity of 42%, are the least humid months in Johnstown.

What is the average humidity in August in Johnstown?

In Johnstown, the average relative humidity in August is 42%.

How many days does it rain in August in Johnstown?

In Johnstown, Colorado, in August, it is raining for 10.9 days, with typically 0.87" (22mm) of accumulated precipitation.

When it does not snow in Johnstown?

In Johnstown, Colorado, snow does not fall in June through September.

What is the average length of the day in August in Johnstown?

In August, the average day length in Johnstown, Colorado, is 13h and 43min.

When is the sunrise / sunset in August in Johnstown?

On the first day of August, sunrise is at 5:58 am and sunset at 8:13 pm. On the last day of the month, sunrise is at 6:26 am and sunset at 7:32 pm MDT.

How long on average sun shines in August in Johnstown?

The average sunshine duration in August in Johnstown is 11.8h.

What is the month with the highest UV index in Johnstown?

The months with the highest UV index in Johnstown are June through August, with an average maximum UV index of 6.

How high is the UV index in August in Johnstown?

The average daily maximum UV index in August in Johnstown, Colorado, is 6. A UV Index of 6 to 7 symbolizes a high health threat from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in August
Johnstown, CO

Average temperature in August - Johnstown, CO
  • Average high temperature in August: 88°F

The warmest month (with the highest average high temperature) is July (88.7°F).
The month with the lowest average high temperature is December (39.4°F).

  • Average low temperature in August: 59°F

The month with the highest average low temperature is July (61.3°F).
The coldest month (with the lowest average low temperature) is December (20.7°F).

Average pressure in August
Johnstown, CO

Average pressure in August - Johnstown, CO
  • Average pressure in August: 29.98"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).

Average wind speed in August
Johnstown, CO

Average wind speed in August - Johnstown, CO
  • Average wind speed in August: 5.7mph

The windiest month (with the highest average wind speed) is April (7.3mph).
The calmest month (with the lowest average wind speed) is December (5.5mph).

Average humidity in August
Johnstown, CO

Average humidity in August - Johnstown, CO
  • Average humidity in August: 42%

The months with the highest relative humidity are January, February and December (63%).
The months with the lowest relative humidity are August and September (42%).

Average rainfall in August
Johnstown, CO

Average rainfall in August - Johnstown, CO
  • Average rainfall in August: 0.87"

The wettest month (with the highest rainfall) is May (2.13").
The driest months (with the least rainfall) are January and December (0.39").

Average rainfall days in August
Johnstown, CO

Average rainfall days in August - Johnstown, CO
  • Average rainfall days in August: 10.9 days

The month with the highest number of rainy days is May (14.3 days).
The month with the least rainy days is November (3.7 days).

Average snowfall in August
Johnstown, CO

Average snowfall in August - Johnstown, CO
  • Average snowfall in August: 0"

The month with the highest snowfall is February (4.53").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in August
Johnstown, CO

Average snowfall days in August - Johnstown, CO
  • Average snowfall days in August: 0 days

The month with the highest number of snowfall days is February (9.6 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in August /
Average sunshine in August
Johnstown, CO

Average daylight in August / Average sunshine in August - Johnstown, CO
  • Average daylight in August: 13h and 4min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in August: 11h and 5min

The month with the most sunshine is June (Average sunshine: 11h and 54min).
The month with the least sunshine is February (Average sunshine: 6h and 42min).

Average sunshine days in August
Johnstown, CO

Average sunshine days in August - Johnstown, CO
  • Average sunshine days in August: 12.1 days

The month with the most sunshine days is January (22.4 days).
The month with the least sunshine days is July (11.4 days).

Average UV index in August
Johnstown, CO

Average UV index in August - Johnstown, CO
  • Average UV index in August: 6

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in August
Johnstown, CO

Average cloud cover in August - Johnstown, CO
  • Average cloud cover in August: 17

The month with the most cloud cover is April (Cloud cover 27).
The months with the least cloud cover are June and September (Cloud cover 16).

Average visibility in August
Johnstown, CO

Average visibility in August - Johnstown, CO
  • Average visibility in August: 6mi

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

Johnstown, Colorado, USA

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