Mount Pinatubo Timeline per Encyclopedia Britannica

March 15. 1991 – Swarm of small earthquakes on Northwest side of Pinatubo
April 2 – Steam explosions opened vents
June 1 – New swarm of earthquakes
June 3 – Small explosion
June 7 – Eruption of steam and ash
June 12 – Major eruption and major explosion
June 15 – Typhoon. Climatic eruption, early afternoon.