Dry air is back, not only heating us up during the day, but also allowing for some cooler mornings. The muggy monsoonal moisture kept clouds in play and dewpoints up. Both contributing to warm overnight lows earlier this month.
The average overnight low in Reno is 61 degrees in the end of July, but we’ve been closer to 70 degrees for a couple weeks. However, for the first time in a while, on July 27th, the low was 58 degrees at the Reno Airport. The low in Reno was even 70 degrees on July 19th and 20th.
Dewpoints the last couple of weeks have also been higher than normal, at times reaching 60 degrees. Which would be considered slightly muggy for much of the country, east of the Rockies. For us in Northern Nevada that is very muggy. The dewpoint is the point at which saturation occurs. A high dewpoint, means the temperature doesn’t have to drop very much to reach saturation.
Now our dewpoints are very low, and at times even reaching the single digits. This is very dry air. Warm air can hold more moisture. So muggy climates are usually warmer at night. They are also slower to warm during the day. For example, while it is very muggy in Miami, the daytime high is usually not as high. Dewpoints in Miami can very easily reach the 70’s.