Abstract: The results of measurements of surfaceconcentrations of nitrogen oxides NO _x (NO and NO ₂)performed at the atmospheric monitoring station near Saint Petersburg(Petergof, 59.88° N, 29.83° E) in 2012–2018 are presented. The mainpatterns of the temporal variability of NO _x concentrationstypical for the urban atmosphere of a large megacity (seasonal, daily,and weekly variations) are revealed. On average, NO _xconcentrations in summer are lower than in the cold season. The averagedaily variations are characterized by two pronounced peaks: in themorning and late at night, which are separated by the periods ofrelatively low concentrations during the day and early in the morning.The weekly variations in NO _x concentration due to the cyclicpattern of urban economic and business activity are manifested in anoticeable decrease in the average NO _x concentration onSunday relative to its maximum level on weekdays (by 17% forNO ₂ and by 33% for NO). Based on the distribution of theaverage NO _x concentration depending on the directions ofsurface wind, a rough estimate of the average NO ₂concentration in Saint Petersburg was obtained: 41 µg/m ³,which is close to the average annual maximum permissible concentration(40 µg/m ³).