It was a scorcher in Tallinn with a temperature of 31 C, while Kunda set a new national record for the month of May - 33.6 C.
The previous record dated from 2007 in Pärnu - 31.2 C.
The Estonian capital, at 59 degrees north latitude, easily beat out Rome, Valletta and a number of other EU capitals that could manage only 22 C. Riga was second-warmest.
The heat, accompanied by slightly hazy sunshine, came from a pocket of high pressure localized over the eastern Baltic, which also sent temperatures into the high 20s for a second straight day in the coastal towns of Haapsalu and Pärnu.
Thunderstorms and hail were forecast in parts of the country on Monday evening, while Saaremaa and Hiiumaa experienced torrential rain and hail this morning and had a cooler day from 18-24 C.
Relief is in sight, but not necessarily tomorrow. Tuesday will bring a chance of thunderstorms again and highs of 17-30 C. The high range will be experienced in the northeast, while Tallinn should be around 24 C. Wednesday and Thursday are looking like 13-23 C with chance of scattered showers.
After a chilly stretch for the past few weeks, nights are expected to be in the 9-15 C range all week.