diff --git a/README.md b/README.md
index aa86f64c6..52ce10b38 100644
--- a/README.md
+++ b/README.md
@@ -22,21 +22,21 @@ A generic event data model for future HEP collider experiments.
 
 | | | |
 |-|-|-|
-| [EventHeader](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L145)         | [MCParticle](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L155)        | [SimTrackerHit](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L224)         |
-| [CaloHitContribution](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L266) | [SimCalorimeterHit](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L278) | [RawCalorimeterHit](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L290)     |
-| [CalorimeterHit](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L299)      | [ParticleID](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L311)        | [Cluster](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L324)               |
-| [TrackerHit](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L345)          | [TrackerHitPlane](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L362)   | [RawTimeSeries](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L383)                |
-| [Track](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L396)               | [Vertex](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L415)            | [ReconstructedParticle](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L432) |
-| [SimPrimaryIonizationCluster](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L536) | [TrackerPulse](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L570) | [RecIonizationCluster](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L583) |
-| [TimeSeries](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L594) | [RecDqdx](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L606) |                                                                                          |
+| [EventHeader](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L145)         | [MCParticle](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L157)        | [SimTrackerHit](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L226)         |
+| [CaloHitContribution](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L268) | [SimCalorimeterHit](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L280) | [RawCalorimeterHit](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L292)     |
+| [CalorimeterHit](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L301)      | [ParticleID](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L313)        | [Cluster](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L326)               |
+| [TrackerHit](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L347)          | [TrackerHitPlane](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L364)   | [RawTimeSeries](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L385)                |
+| [Track](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L398)               | [Vertex](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L417)            | [ReconstructedParticle](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L434) |
+| [SimPrimaryIonizationCluster](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L538) | [TrackerPulse](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L572) | [RecIonizationCluster](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L585) |
+| [TimeSeries](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L596) | [RecDqdx](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L608) |                                                                                          |
 
 **Associations**
 
 | | | |
 |-|-|-|
-| [MCRecoParticleAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L462)        | [MCRecoCaloAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L471)         | [MCRecoTrackerAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L480)         |
-| [MCRecoTrackerHitPlaneAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L489) | [MCRecoCaloParticleAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L498) | [MCRecoClusterParticleAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L507) |
-| [MCRecoTrackParticleAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L516)   | [RecoParticleVertexAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L525) |                                                                                                      |
+| [MCRecoParticleAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L464)        | [MCRecoCaloAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L473)         | [MCRecoTrackerAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L482)         |
+| [MCRecoTrackerHitPlaneAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L491) | [MCRecoCaloParticleAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L500) | [MCRecoClusterParticleAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L509) |
+| [MCRecoTrackParticleAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L518)   | [RecoParticleVertexAssociation](https://github.com/key4hep/EDM4hep/blob/main/edm4hep.yaml#L527) |                                                                                                      |
 
 The tests and examples in the `tests` directory show how to read, write, and use these types in your code.
 
diff --git a/edm4hep.yaml b/edm4hep.yaml
index 0c05dc822..ea2042af1 100644
--- a/edm4hep.yaml
+++ b/edm4hep.yaml
@@ -149,7 +149,9 @@ datatypes:
       - int32_t eventNumber    //event number
       - int32_t runNumber      //run number
       - uint64_t timeStamp     //time stamp
-      - float weight       // event weight
+      - double weight       // event weight
+    VectorMembers:
+      - double weights       // event weights in case there are multiple. **NOTE that weights[0] might not be the same as weight!** Event weight names should be stored using the edm4hep::EventWeights name in the file level metadata.
 
 
   edm4hep::MCParticle:
diff --git a/include/edm4hep/Constants.h b/include/edm4hep/Constants.h
index 48b09d6dc..81dde40ea 100644
--- a/include/edm4hep/Constants.h
+++ b/include/edm4hep/Constants.h
@@ -22,6 +22,7 @@
 namespace edm4hep {
 static constexpr const char* CellIDEncoding = "CellIDEncoding";
 static constexpr const char* EventHeaderName = "EventHeader";
+static constexpr const char* EventWeights = "EventWeightNames";
 } // namespace edm4hep
 
 #endif // EDM4HEP_CONSTANTS_H