Summer weather in the mountains can be very unpredictable. Summer showers are more frequent, even on summer days. Follow the weather forecast for the Julian Alps. https://meteo.arso.gov.si/met/en/weather/fproduct/ and regularly check the radar image of perception https://meteo.arso..ov.si/met/en/.
Link to the Slovenian Environmental Agency: http://www.arso.gov.si/