My serama seem to do fine in high temperatures, given that they have access to water at all times, and are housed in a shady pen. In temperatures of 43, 40, 39 degrees Celsius they did not need anything else, such as hosing down their pen, taking them in the house, etc. By keeping a close eye on them, and watching out for signs of overheating, you'll be fine (provided that your serama are acclimated to your environment)
Thanks for the tag,
@BDutch ! I'd be happy to answer any more questions the OP might have. I am, however, a man, not a woman