diff --git a/sql/migration.sql b/sql/migration.sql
index 0df4eb2bcd4cadbf9f797d7810d703faaa9f693e..a3f274ce369a0efc0bb916f13faa4e90f0e5e588 100644
--- a/sql/migration.sql
+++ b/sql/migration.sql
@@ -219,6 +219,31 @@ END;
 $BODY$
 language plpgsql;
 
+--
+-- #96 : periods
+--
+CREATE OR REPLACE FUNCTION upgrade20250116() RETURNS boolean AS $BODY$
+BEGIN
+    CREATE TEMPORARY TABLE IF NOT EXISTS tmp_translation (
+        key VARCHAR,
+        locale VARCHAR,
+        translation VARCHAR
+    );
+    INSERT INTO tmp_translation (key, locale, translation) VALUES
+    ('summer', 'en', 'Summer crop (01/04 − 15/10)'),
+    ('summer', 'fr', 'Culture d’été (01/04 − 15/10)'),
+    ('winter', 'en', 'Winter crop (31/10 − 31/8)'),
+    ('winter', 'fr', 'Culture d’hiver (31/10 − 31/8)');
+
+	UPDATE i18n
+    	SET translation=t.translation
+    	FROM i18nkey AS k, locale AS l, tmp_translation AS t
+    	WHERE i18n.i18nkey=k.id AND i18n.locale=l.id AND l.languagetag=t.locale AND k.string=t.key;
+    RETURN true;
+END;
+$BODY$
+language plpgsql;
+
 ---
 --
 -- Keep this call at the end to apply migration functions.
diff --git a/sql/translations.csv b/sql/translations.csv
index 0181ecf27c8559fe6967baf53825d5b29dccab87..4eeafc6079174dcd0d2bf510490fb53174c9b962 100644
--- a/sql/translations.csv
+++ b/sql/translations.csv
@@ -27,11 +27,9 @@ rainsum,en,Rain sum
 rainsum,fr,Cumul de pluie
 rainsum-description,en,Total precipitation
 rainsum-description,fr,Cumul des précipitations
-spring,en,Spring
-spring,fr,Printemps
-summer,en,Summer
-summer,fr,Été
-winter,en,Winter
-winter,fr,Hiver
+summer,en,Summer crop (01/04 − 15/10)
+summer,fr,Culture d’été (01/04 − 15/10)
+winter,en,Winter crop (31/10 − 31/8)
+winter,fr,Culture d’hiver (31/10 − 31/8)
 year,en,Year
 year,fr,Année
diff --git a/www-client/src/main/java/fr/agrometinfo/www/client/ui/chart/DailyValuesChart.java b/www-client/src/main/java/fr/agrometinfo/www/client/ui/chart/DailyValuesChart.java
index 6e9d2dca2d78e35c46b80fc58a3a1da8219cacdf..76f08c030e84021faaa2beac76bff513d50bc025 100644
--- a/www-client/src/main/java/fr/agrometinfo/www/client/ui/chart/DailyValuesChart.java
+++ b/www-client/src/main/java/fr/agrometinfo/www/client/ui/chart/DailyValuesChart.java
@@ -69,7 +69,7 @@ public final class DailyValuesChart extends TimeSeriesLineChart {
         GWT.log("DailyValuesChart() " + values.size());
         this.unit = summary.getIndicator().getUnit();
 
-        final var subtitle = MSGS.chartSubtitle(summary.getDate(), unit);
+        final var subtitle = new String[] {summary.getPeriod(), MSGS.chartSubtitle(summary.getDate(), unit)};
         setTitle(CSTS.dailyValues() + " − " + DateUtils.getYear(summary.getDate()), subtitle);
         setPlugins();
 
@@ -125,7 +125,7 @@ public final class DailyValuesChart extends TimeSeriesLineChart {
         this.getPlugins().add(new LogoPlugin());
     }
 
-    private void setTitle(final String title, final String subtitle) {
+    private void setTitle(final String title, final String[] subtitle) {
         this.getOptions().setResponsive(true);
         this.getOptions().setAnimationEnabled(false);
         this.getOptions().getLegend().setDisplay(false);