From 270242a685e26e4a678efe8dfb01eb2f0d1de3e6 Mon Sep 17 00:00:00 2001
From: Florian <florian@nocleus.com>
Date: Wed, 27 May 2026 22:09:11 +0200
Subject: [PATCH] =?UTF-8?q?fix(climato):=20TX=20agr=C3=A9g=C3=A9=20par=20M?=
 =?UTF-8?q?AX=20plut=C3=B4t=20que=20moyenne=20inter-stations?=
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La moyenne des TX sur toutes les stations du département sous-estimait
systématiquement de 2-3°C à cause des stations en altitude. MAX est
la sémantique correcte pour un site canicule.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 src/lib/climato.ts | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/lib/climato.ts b/src/lib/climato.ts
index c38dccb..35c5464 100644
--- a/src/lib/climato.ts
+++ b/src/lib/climato.ts
@@ -37,7 +37,7 @@ function buildUrl(dept: string, period: string): string | null {
   return `${BASE}/Q_${dept}_${period}_RR-T-Vent.csv.gz`;
 }
 
-type Agg = { tnSum: number; tnN: number; txSum: number; txN: number; tmSum: number; tmN: number; rrSum: number; rrN: number; stations: number };
+type Agg = { tnSum: number; tnN: number; txMax: number; txN: number; tmSum: number; tmN: number; rrSum: number; rrN: number; stations: number };
 
 function parseCsvInto(text: string, byDate: Map<string, Agg>): void {
   const lines = text.split(/\r?\n/);
@@ -60,19 +60,23 @@ function parseCsvInto(text: string, byDate: Map<string, Agg>): void {
     const date = `${raw.slice(0, 4)}-${raw.slice(4, 6)}-${raw.slice(6, 8)}`;
     let agg = byDate.get(date);
     if (!agg) {
-      agg = { tnSum: 0, tnN: 0, txSum: 0, txN: 0, tmSum: 0, tmN: 0, rrSum: 0, rrN: 0, stations: 0 };
+      agg = { tnSum: 0, tnN: 0, txMax: -Infinity, txN: 0, tmSum: 0, tmN: 0, rrSum: 0, rrN: 0, stations: 0 };
       byDate.set(date, agg);
     }
     agg.stations++;
-    const add = (raw: string | undefined, sum: 'tnSum' | 'txSum' | 'tmSum' | 'rrSum', n: 'tnN' | 'txN' | 'tmN' | 'rrN') => {
+    const addAvg = (raw: string | undefined, sum: 'tnSum' | 'tmSum' | 'rrSum', n: 'tnN' | 'tmN' | 'rrN') => {
       if (!raw) return;
       const v = parseFloat(raw.replace(',', '.'));
       if (Number.isFinite(v)) { agg![sum] += v; agg![n]++; }
     };
-    if (idx.tn !== -1) add(cols[idx.tn], 'tnSum', 'tnN');
-    if (idx.tx !== -1) add(cols[idx.tx], 'txSum', 'txN');
-    if (idx.tm !== -1) add(cols[idx.tm], 'tmSum', 'tmN');
-    if (idx.rr !== -1) add(cols[idx.rr], 'rrSum', 'rrN');
+    // TX: max across stations (not average) — hottest reading in the dept for canicule detection
+    if (idx.tx !== -1 && cols[idx.tx]) {
+      const v = parseFloat(cols[idx.tx].replace(',', '.'));
+      if (Number.isFinite(v)) { if (v > agg.txMax) agg.txMax = v; agg.txN++; }
+    }
+    if (idx.tn !== -1) addAvg(cols[idx.tn], 'tnSum', 'tnN');
+    if (idx.tm !== -1) addAvg(cols[idx.tm], 'tmSum', 'tmN');
+    if (idx.rr !== -1) addAvg(cols[idx.rr], 'rrSum', 'rrN');
   }
 }
 
@@ -89,7 +93,7 @@ function aggregateDays(byDate: Map<string, Agg>): DayObservation[] {
     .map(([date, agg]) => ({
       date,
       tn: agg.tnN > 0 ? +(agg.tnSum / agg.tnN).toFixed(1) : null,
-      tx: agg.txN > 0 ? +(agg.txSum / agg.txN).toFixed(1) : null,
+      tx: agg.txN > 0 ? +agg.txMax.toFixed(1) : null,
       tm: agg.tmN > 0 ? +(agg.tmSum / agg.tmN).toFixed(1) : null,
       rr: agg.rrN > 0 ? +(agg.rrSum / agg.rrN).toFixed(1) : null,
       stations: agg.stations,