We provide a preliminary interpretation of the Rover Environmental Monitoring Station (REMS)pressure data from the ﬁrst 100 Martian solar days (sols) of the Mars Science Laboratory mission. The pressuresensor is performing well and has revealed the existence of phenomena undetected by previous missionsthat include possible gravity waves excited by evening downslope ﬂows, relatively dust-free convectivevortices analogous in structure to dust devils, and signatures indicative of the circulation induced by GaleCrater and its central mound. Other more familiar phenomena are also present including the thermal tides,generated by daily insolation variations, and the CO2cycle, driven by the condensation and sublimation ofCO2in the polar regions. The amplitude of the thermal tides is several times larger than those seen by otherlanders primarily because Curiosity is located where eastward and westward tidal modes constructively interfere and also because the crater circulation ampliﬁes the tides to some extent. During the ﬁrst 100 solstidal amplitudes generally decline, which we attribute to the waning inﬂuence of the Kelvin wave. Toward theend of the 100 sol period, tidal amplitudes abruptly increased in response to a nearby regional dust stormthat did not expand to global scales. Tidal phases changed abruptly during the onset of this storm suggestinga change in the interaction between eastward and westward modes. When compared to Viking Lander2 data, the REMS daily average pressures show no evidence yet for the 1–20 Pa increase expected from thepossible loss of CO2from the south polar residual cap.