Paintings from Monet's Houses of Parliament London series have been analysed for the quantitative information they contain, by comparing the depicted position of the Sun with Solar geometry calculations. The positions of roofline features of the Houses of Parliament were measured to provide an internal scale for the determination of azimuthal and elevation angles of the Solar depictions. Despite some distortion of the painted motif, the internal scales were found to be approximately linear. The Solar positions were used to derive the dates and times of the depicted scenes. The results provide new information for assessing these paintings and are consistent with the known period Monet was in London, suggesting that they contain elements of accurate observation and may potentially be considered as a proxy indicator for the Victorian smogs and atmospheric states they depict. The four dates Monet reports observing the Sun over Parliament in 14 and 16 February and 9 and 24 March 1900, are all represented in the series. The analysis also enables Monet's vantage point from St Thomas' Hospital to be determined for the first time.