Save Data to flash at remote site

I need to monitor a location with no mains power or WiFi for a period of time for temperature and humidity. I have a WEMOS D1 Mini connected to a BME680 that does the recording nicely and I know I can optimise the battery running time with deep sleep.

Understanding the limitations on write cycles, is it possible to configure the device to write the data to flash such that it can be recovered later?

I only need something like 30 minute readings for a couple of weeks (if the battery lasts) and the data could simply be written once a day and then a mechanism to read the file later to send on when there is WiFi?

Is it also possible to limit how long the device searches for WiFi (again to optimise battery)?