Recommended citation format: Schnitkey, G.  Cost Cutting for 2016: Budgeting for $4 Corn and $9.25 Soybeans . farmdoc daily (5):141, Department of Agricultural and Consumer Economics, University of Illinois at Urbana-Champaign, August 4, 2015.
Generally: The temperature rise occurs after ovulation, usually about 2 weeks before the period starts. 4. About a week or so before my period starts, during my period and sometimes a few days after ,I run a temperature that ranges 99 - 100.
With ovulation, a rise in body temperature takes place - caused by an increase of the hormone progesterone - in order to provide a warmer, more fertile environment. A minimum temperature rise of 0.4 to 0.6 degrees F can be measured - and this change will last through the duration of the menstrual cycle. By monitoring when this temperature change takes place, you can estimate when ovulation has taken place. You can find a digital basal thermometer designed for BBT charting here.