The National Fire and Civil Protection Service said Tuesday the increased state of readiness was due to forecasts that temperatures would stay above 40 Celsius (104 Fahrenheit) in some areas.
Water-bombing aircraft and soldiers have helped the fire brigade in recent days, mostly in northern and central areas.
Firefighters brought a major blaze under control Tuesday but five others were still raging.
The fire service was placed on alert last week as temperatures soared. On Sunday, the fire service logged 546 wildfires and deployed more than 7,500 firefighters, the AP reports.
In July, six firefighters died in a forest fire.
The Bulgarian authorities made a stupid and absurd decision when they did not let a government flight with official representative of the Russian Ministry of Foreign Affairs Maria Zakharova on board fly to North Macedonia