Surface temperatures are key parameters in many applications of concentrated solar radiation. Pyrometric temperature determination is, however, hampered by reflected solar radiation. Two approaches to solve this problem were experimentally tested on a solar reactor at the Paul Scherrer Institute (PSI): the flash assisted multi-wavelength pyrometry (FAMP) developed at PSI and a solar-blind pyrometer developed by the IMPAC Electronic GmbH in Frankfurt, Germany, in collaboration with PSI. Performance, advantages, and disadvantages of the two pyrometers are reported and discussed.