diff --git a/src/OnlineStatsBase.jl b/src/OnlineStatsBase.jl
index 67e9ad7..c1fc99e 100644
--- a/src/OnlineStatsBase.jl
+++ b/src/OnlineStatsBase.jl
@@ -4,7 +4,7 @@ module OnlineStatsBase
 using NamedTuples
 
 #-----------------------------------------------------------------------# Data
-const ScalarOb = Union{Number, AbstractString, Symbol}  # 0
+const ScalarOb = Union{Number, AbstractString, Symbol, Dates.TimeType}  # 0
 const VectorOb = Union{AbstractVector, Tuple, NamedTuple} # 1 
 const XyOb     = Tuple{VectorOb, ScalarOb}              # (1, 0)
 const Data = Union{ScalarOb, VectorOb, AbstractMatrix, XyOb}