Annual threshold for extreme heavy precipitation in rainy season: Let RRt be the daily precipitation amount on day t. For R99prs list all RRt of one year, but only in rainy season (which means rs1_ons≤t≤rs1_ces or rs2_ons≤t≤rs2_ces, for climatological rs1_ons, rs1_ces, rs2_ons, rs2_ces) and take the 99th percentile value.