early on i stay on the lower end of recommendations of 76F for the heating mat, but i stop using it after first transplant into 1 gal pot. Bet they are 70-72ish with lights on? due to evaporation the substrate will be slightly cooler than the atmosphere... if a light or sun is shining on the pot and topsoil, that would have its own measurable effect, too.
above ground you want 25-30C and proper vpd (this is optimal for photosynthesis), or if not controlling that... don't worry about it at all and go with the flow. if you aren;t going to adjust your house thermostat or invest in portable heat/ac etc.. then it's going to be what it will be.
Hope you get enough light, or they'll be super lanky in 4-5 weeks. Might have some sterss under intensity of sun, initially, too. Colder atmosphere will stunt their growth above while a warm substrate will continue to push root growth... maybe, some bit of this would keep them from stretching like crazy, but still add a bunch of root mass between now and end of May. that would still give it a very good start outside.. growth above ground at that point would be accelerated initially, i bet.