Twenty‐three lowland streams throughout the Waikato region, New Zealand, in catchments having a wide range of land uses and intensities, were monitored continuously over 3–4‐day periods for changes in dissolved oxygen (DO) and temperature. A single‐station diurnal curve model, DOFLO (Dissolved Oxygen at Low Flow), was used to produce reach‐averaged values for:K2(20), the reaeration coefficient at 20°C;Pmax., the maximum daily rate of photosynthetic production of oxygen;R20, the daily respiration rate at 20°C; andQ10, the ratio of respiration rates 10°C apart. In addition, 24‐h average values for the ratioP/Rwere calculated and maximum and minimum values of DO and temperature tabulated for each site. Values ofK2(20)(0.05–40 d‐1, median 6.0 d‐1) were in broad agreement with values calculated using a modified form of the O'Connor‐Dobbins equation. Values of gross primary production in daylight (0.5–29.2 g m‐2d‐1) calculated fromPmax. (1.75–86.5 g m‐3d‐1) were similar to data reported for other streams in agriculturally developed catchments in New Zealand and North America. Respiration rates (3.50–55.0 g m‐3d‐1) were generally larger than values reported in the literature, andP/Rratios were mostly well below 1.0, indicative of heterotrophic respiration associated with decaying vegetation and other organic inputs and consistent with diurnal DO excursions of 40 to ≥120% saturation being commonly observed. Maximum daily temperatures up to 25.7°C (median 20.5°C) were weakly negatively correlated with DO minima. Five groupings of streams were identified from DOFLO parameter values, withK2(20)being most critical in regulating average DO deficits.