Saturday, April 27, 2013

Increased Days, Stronger Sun...Solar Summer Is Almost Upon Us

Solar summer, the three month period of time where the sun's energy is strongest in the northern hemisphere, is almost upon us.  From May 6th through August 6th, the peak of the sun's angle in the sky is above 66 degrees at 1 PM (solar noon), providing us the three months of most intense solar energy that we see during the year.

Sunburns, which can happen almost any time of the year, will increase in ease and frequency over the next few weeks as temperatures warm and the sun continues its journey higher in our sky through June 21st.  The result will be an increase in the UV index for us for the next seven weeks.  The UV index measures the level of ultraviolet radiation that is reaching the surface...the rays that can torch your skin and can result in skin damage and perhaps skin cancer.  UV radiation is more intense to our south, closer to the path of most direct sunlight, and is also higher over the deserts of the US Southwest as a drier atmosphere results in less water vapor to absorb solar radiation, thus allowing for a greater risk of burns.

UV Index forecast for the US for today. Source: EPA
Our day length is now officially longer than it is in the middle of August, with our first sub 6 AM sunrise due on May 2nd.  We'll see earlier sunrises for the next six weeks before we stop at 5:31 AM between June 11th and June 16th.  Sunsets will continue to work deeper into the evening until we reach 8:33 PM towards the end of June.  However, our peak day length is 15 hours and a minute, occurring for a couple of days around the summer solstice.  However, we will have fourteen hours or more of daylight from May 4th through August 7th.

If you can't stand longer days, wait a few months and it will gradually change...again.