New Lawn - cracks

I sowed grass seed last week when the weather was cool and damp - this week we have the opposite...my grass seed is germinationg well and I am watering the area every evening (watering can with fine rose). However cracks are appearing in parts of the seed bed not more than a couple of millimetres wide but they are there. I am thinking this may be due to the hot weather we ware now experiencing - I'm in SE. What should I do? Could I pour horticultural sand into the cracks? Any advice welcome. Thanks.

This is quite normal it will correct its self. Continue to water every day in this heat - twice a day would be better.

Thanks Marshmello. I am going to invest in a sprinkler as I can't keep the soil wet enough at the moment - by the time I have watered the whole lawn the first bit has already dried out. Am now watering early morning and evening ...but it is not enough. We luckily are just outside the hosepipe ban area!