by John Simpson
April was warmer than average and drier than average in southeast Arizona. Much of the Tucson area received no measurable rain during April, and the National Weather Service in Tucson recorded the second warmest April since records began in the 1880’s. In addition, this is only the 12th April in the last 130+ years where no measurable rain fell. The Weather Service in Tucson also listed this interesting fact in their April 2018 climate report, “For the first time since 1895, March and April combined for only a trace of rain at the official recording spot in Tucson.” Fortunately, the nearly three inches of rain that fell in much of the Vail area in late February provided the vegetation with much-needed moisture. This allowed for a decent desert flower show. Not the best, but decent. The month of June typically averages the hottest daytime highs. The average daily high at the Tucson airport for June is around 100 degrees. The average daily low of around 69 degrees for June is much cooler than the average lows for July and August due to the drier air prior to the monsoon. Drier air allows for cooler nights. At the time of this writing, there are no strong forecast signals to provide guidance on what we can expect for the 2018 monsoon. Sometimes the welcome thunderstorms arrive in late June, sometimes they do not arrive until July. Next month I will discuss the weather we had in May and give a brief discussion on the monsoon that we experience every summer.