his study describes the response of Arthrospira platensis to a variety of temperature conditions as reflected in variations of photosynthetic parameters, pigmentation, and biomass productivity in indoor photobioreactor (PBR) cultivations. These experiments are designed to better understand the impact of temperature, seasonal variations, and acclimation effects on outdoor biomass production. The irradiance levels and temperature range (20 – 39°C) are chosen to enable modeling of semi-continuous operation of large-scale outdoor PBR deployments. Overall, the cultivations were quite stable with some pigment-related instabilities after prolonged high temperature exposure. Changes in productivity with temperature, as reflected in measured photosynthetic parameters, are immediate and mainly attributable to the temperature dependence of the photosaturation parameter, a secondary factor being variation in pigment content. This study confirms that temperature is critical for optimal performance of Arthospira platensis for both biomass and pigment production and provides a basis for risk assessments related to temperature mitigation for large-scale outdoor cultivations. Finally, the biomass productivities in a semi-continuous operation mode are quantitatively reproduced with a productivity model incorporating the photosynthetic parameters measured herein. Those productivities are in good agreement with extensive outdoor testing in PBR arrays at large scale (24,000 L) and over long time periods (up to 18 months).