How many days with frost were there in the City/Town of Lugo have?
CREATE TABLE "climate" (
  "city_town" text,
  "july_av_t" text,
  "rain" text,
  "days_with_rain_year_summer" text,
  "days_with_frost" real,
  "sunlight_hours" real
);
SELECT SUM("days_with_frost") FROM "climate" WHERE "city_town"='lugo';