98 years ago today. The Prince of Wales was on a two-month tour of India and Japan and is photographed here meeting Lord Rawlinson, Commander-in-Chief of Indian Forces, in a very interesting military hat (even more interesting in combination with those plaid trousers!)
Photo from Getty as indicated
Royal Hats 
HQ you prompted me to read up about the pith helmet. it’s interesting how it fell out of favour (among western wearers), apparently because of its associations with colonialism. I wasn’t aware that in the colonial era, the pith helmet was not just worn “on safari” or as military uniform; it seems it was worn by western men in hot climates, paired with all sorts of dress. This video of the Prince’s 1920 tour of India shows racegoers in Calcutta wearing their business suits with pith helmets 12:09; and a sight I would never have believed, had I not viewed it — the Prince of Wales wearing a pith helmet with morning dress! 13:55-14:19 https://www.youtube.com/watch?v=OVF_nHqPcss
BTW, those plaid trousers just get more interesting; they are actually riding jodphurs – see pic here: https://www.mirror.co.uk/news/uk-news/nearest-thing-monkeys-edward-viiis-3829747. Plaid trousers are traditional Scottish dress; but jodphurs originated in India… perhaps tartan jodphurs were an innovation of the Prince? certainly they were an appropriate choice for this tour. https://www.mirror.co.uk/news/uk-news/nearest-thing-monkeys-edward-viiis-3829747
Perhaps the plaid is a regimental tartan? In any case, it’s certainly the 1920s equivalent of “a lot of look.”