Welcome to the month of June, where meteorological and astronomical summer begin, respectively. If you do not know that there was ever a difference, here is some information from Scott Martin, a meteorologist in Central Alabama.
ASTRONOMICAL SUMMER: THURSDAY, JUNE 21ST – SATURDAY, SEPTEMBER 22ND
The natural rotation of the Earth around the sun forms the basis for the astronomical calendar, in which we form the seasons by two solstices and two equinoxes. Earth’s tilt and the sun’s alignment over the equator determine both the solstices and equinoxes. Equinoxes mark when the sun passes directly over the equator, whereas solstices mark when the sun is farthest away from the equator. Since the Earth actually takes 365.24 days to travel around the sun, an extra day is needed every fourth year, creating “Leap Year.” This, along with the elliptical shape of the Earth’s orbit, makes the actual number of days in each season to vary between 89 to 93 days. This makes it difficult to compare climatological statistics consistently for a particular season from one year to next. That is why there is a need for meteorological seasons.
METEOROLOGICAL SUMMER: FRIDAY, JUNE 1ST – FRIDAY, AUGUST 31ST
Meteorologists and climatologists group the seasons in three month sections (or seasons) based on the calendar and on the annual temperature cycle. Forecasting and observing led to these seasons being created. Meteorological season length is more consistent between the four seasons as they are close to 90 days for each season. With less variation in start date and in season length, its much easier to calculate seasonal statistics from monthly statistics, both of which are very useful for agriculture, commerce, and a variety of other purposes.
Now, let the June explanation begin.
On average, June is the second warmest month of the year (go figure) featuring mostly hot temperatures with humidity staying at around normal levels for the summer.
Contrary to popular belief, June is actually the second wettest month of the year in Dallas, right behind October. We usually average about 3.92 inches of rain during the month, but the wettest June on record saw 11.58 inches of rain back in 1928. For DFW airport, where records have been kept there for over 100 years, the wettest month there was June 2007, where 11.10 inches fell. Additionally, any tropical systems that happen to end up in Texas from the Gulf of Mexico has significantly shifted the rain total for the month in years past.
June is also the second sunniest month of the year (on average), with a total of 23 days with possible sunshine. The average afternoon humidity starts to come down during the summer time months. 48% for the month of June, which is a decrease from the 53% in May.
For the first day of June, the average high is about 88 degrees and the average low is 69. When we get to the end of the month, the average high increases to 95 and the average low increases to 75. The hottest high for June was observed on June 26 and 27, 1980, when we reached 105 degrees for the day. It has been as cold as 53 degrees for the morning low on June 1, 1982.
As you may know, June 1st marks the first day of the Atlantic Hurricane Season, which stretches out until November 30. Two weeks ago, NOAA came out with their official hurricane season forecast, calling for a normal or above-normal season this year. More specifically, their thinking is that 10 to 16 tropical cyclones will end up named, 5 to 9 of those storms will intensify to hurricane strength, and 1 to 4 could intensify to even major hurricane status.
Since Alberto was the first storm named this year, we will kick off the hurricane season on the second name when the time comes. We will have to wait and see if Beryl will form in the Gulf during the next week or so.