The hot weather is thankfully little bit late this year, but the hot weather in Sydney yesterday is a timely reminder to provide shade and moisture curing to your tiling.
We know that the optimal temperature for curing concrete is about 22 degrees. If shade is not provided, the surface temperature of a screed or tile can quickly exceed 50 degrees. Mortar needs to cure, not to bake. Tilers don't need to bake either!
The other obvious risk of not providing shade, is the loss of hydration. If we lose the construction moisture, the chemical reaction stops and we can expect our screeds and grouts to go powdery.
As soon as a screed is in place, it's important to keep providing shade and moisture curing, with something like wet hessian. Especially when you're using Efflock, once the moisture evaporates out, you cannot put it back (not that putting water back into a standard screed would be good practice either).
Australian Standard AS 3958.1-2007 (Guide to the installation of ceramic tiles) says: "Sand/cement and fine concrete screeds should be cured for at least 7 days and be subjected to continuous air-drying after curing for at least 2 weeks before the bed and tiling are applied." (See Appendix A, on page 93).
Grout is also susceptible. Clause 5.7.3 on page 89 says: "All cement-based tile installations, including Portland cement grouts, should be damp cured for 48h minimum, unless otherwise specified." In addition to that, we would flag that it's worth considering the tile that is being grouted. Natural stone tiles can often contribute to the loss of hydration by sucking moisture out of the grout. The use of pre-sealers on stone, and or liquid polymer grout additives (i.e. SBR latex) can help to mitigate the premature loss of moisture.