diff --git a/main/main.c b/main/main.c
index fd9ed60..8824090 100644
--- a/main/main.c
+++ b/main/main.c
@@ -78,6 +78,9 @@ void read_from_dht22() {
       latest_datapoint.rh = dht22_relative_humidity();
 
       if (has_ntp_time_obtained_once()) {
+        // I _think_ I only want to be doing that rolling average and saving if/when
+        // we've got an actual time to do that with. I think that'd avoid some weird
+        // bugs (time changing from 1970 -> current time within a 10 min period)
         time_t epoch;
         time(&epoch);
         struct tm *timeinfo = localtime(&epoch);
@@ -89,10 +92,20 @@ void read_from_dht22() {
         latest_datapoint.time.myt_day   = timeinfo->tm_mday;
         latest_datapoint.time.myt_month = timeinfo->tm_mon;
         latest_datapoint.time.myt_year = timeinfo->tm_year;
-        // TODO: update ten minute rolling average
-        //
-        // TODO: Write the data out somewhere - into RAM maybe - I think only every 10 minutes
-        // though
+
+        if (num_samples_last_ten_mins == 0) {
+          ten_minute_rolling_average.rh = latest_datapoint.rh;
+          ten_minute_rolling_average.temp = latest_datapoint.temp;
+        } else {
+          ten_minute_rolling_average.rh +=
+              (latest_datapoint.rh - ten_minute_rolling_average.rh) /
+              num_samples_last_ten_mins;
+          ten_minute_rolling_average.temp +=
+            (latest_datapoint.temp - ten_minute_rolling_average.temp) / num_samples_last_ten_mins;
+        }
+        num_samples_last_ten_mins += 1;
+        // TODO: If 10 minute average taken, save it and reset num_samples and ten_min_av
+        // TODO: Write the data out somewhere - into RAM maybe
       }
     }
     vTaskDelay(pdMS_TO_TICKS(CONFIG_DHT22_PERIOD_POLL));