Archives
Categories
WeatherGuys Links
Category Archives: Seasons
What is a heat wave?
A heat wave is a period of abnormally and uncomfortably hot and usually humid weather. The World Meteorological Organization is specific in its definition by stating that a heat wave is when the daily maximum temperature for more than five consecutive days exceeds the average maximum temperature by 9 degrees.
Heat waves are caused by very hot, stagnant air masses. Regions that suffer under intense hot spells are usually dominated by a surface high-pressure system with a mid-tropospheric ridge aloft. Dew points are also high, and to compound matters, wind speeds are often low. Continue reading
What is the heat index?
The heat index indicates how hot it feels. It is expressed as a function of air temperature and the relative humidity.
The heat index temperature is for standing in the shade; when exposed to direct sunlight, the heat index value can be increased by up to 15 degrees. Continue reading
How do you measure how hot the summer is?
After experiencing our first 90-degree day of the season on Friday, many people are wondering what we might expect this summer.
It turns out that the number or 90-degree days each summer is extremely variable here in Madison. From 1971 to 2015, the average number of days at or above 90 in Madison was 10.96. This average, however, struggles to convey a sense of the variability. Continue reading
Is our growing season getting longer?
Yes. There are several studies that demonstrate shifts in the timing and length of the growing season.
One way to measure the length of the growing season is to count the number of days between the last frost in spring and the first frost in fall. By this measure, Wisconsin’s growing season lengthened by about 12 days between 1950 and 2006. Continue reading
When can it get really hot in southern Wisconsin?
Our cold early April seems to have finally given way to a surging spring. Now that we have seemingly emerged from winter, with reasonable confidence that we will not go back, it is interesting to consider when truly summerlike weather might first appear in southern Wisconsin.
One measure of summer here is a daytime high temperature at or above 90 degrees. In Madison, there have been only three April days when the high temperature was that warm. Continue reading
Category: Climate, Meteorology, Seasons
Comments Off on When can it get really hot in southern Wisconsin?
Comments Off on When can it get really hot in southern Wisconsin?
