diff --git a/docs/src/callbackmanager.md b/docs/src/callbackmanager.md
index 3ad4307e..ff748caa 100644
--- a/docs/src/callbackmanager.md
+++ b/docs/src/callbackmanager.md
@@ -7,10 +7,12 @@ functions from Julia's [Dates](https://docs.julialang.org/en/v1/stdlib/Dates/) m
 ## CallbackManager API
 
 ```@docs
+ClimaUtilities.CallbackManager.HourlyCallback
+ClimaUtilities.CallbackManager.MonthlyCallback
+ClimaUtilities.CallbackManager.Monthly
+ClimaUtilities.CallbackManager.EveryTimestep
 ClimaUtilities.CallbackManager.to_datetime
 ClimaUtilities.CallbackManager.strdate_to_datetime
 ClimaUtilities.CallbackManager.datetime_to_strdate
 ClimaUtilities.CallbackManager.trigger_callback
-ClimaUtilities.CallbackManager.Monthly
-ClimaUtilities.CallbackManager.EveryTimestep
 ```
diff --git a/src/CallbackManager.jl b/src/CallbackManager.jl
index bd38f24f..955336b6 100644
--- a/src/CallbackManager.jl
+++ b/src/CallbackManager.jl
@@ -8,64 +8,71 @@ module CallbackManager
 
 import Dates
 
-export to_datetime,
-    strdate_to_datetime,
-    datetime_to_strdate,
-    trigger_callback,
+export HourlyCallback,
+    MonthlyCallback,
     Monthly,
-    EveryTimestep
+    EveryTimestep,
+    trigger_callback,
+    to_datetime,
+    strdate_to_datetime,
+    datetime_to_strdate
 
 """
-    to_datetime(date)
+    AbstractCallback
+"""
+abstract type AbstractCallback end
 
-Convert a `DateTime`-like object (e.g. `DateTimeNoLeap`) to a `DateTime`.
-We need this since some data files we use contain
-`DateTimeNoLeap` objects for dates, which can't be used for math with `DateTime`s.
-The `DateTimeNoLeap` type uses the Gregorian calendar without leap years, while
-the `DateTime` type uses Gregorian calendar with leap years.
+"""
+    HourlyCallback{FT}
 
-For consistency, all input data files should have dates converted to `DateTime`
-before being used in a simulation.
+This is a callback type that triggers at intervals of 1h or multiple hours.
+"""
+@kwdef struct HourlyCallback{FT} <: AbstractCallback
+    """ Time interval at which the callback is triggered. """
+    dt::FT = FT(1) # hours
+    """ Function to be called at each trigger. """
+    func::Function = do_nothing
+    """ Reference date for the callback. """
+    ref_date::Array = [Dates.DateTime(0)]
+    """ Whether the callback is active. """
+    active::Bool = false
+    """ Data to be passed to the callback function. """
+    data::Array = []
+end
 
-This function is similar to `reinterpret` in CFTime.jl.
+"""
+    MonthlyCallback{FT}
 
-# Arguments
-- `date`: `DateTime`-like object to be converted to `DateTime`
+This is a callback type that triggers at intervals of 1 month or multiple months.
 """
-function to_datetime(date)
-    return Dates.DateTime(
-        Dates.year(date),
-        Dates.month(date),
-        Dates.day(date),
-        Dates.hour(date),
-        Dates.minute(date),
-        Dates.second(date),
-        Dates.millisecond(date),
-    )
+@kwdef struct MonthlyCallback{FT} <: AbstractCallback
+    """ Time interval at which the callback is triggered. """
+    dt::FT = FT(1) # months
+    """ Function to be called at each trigger. """
+    func::Function = do_nothing
+    """ Reference date for the callback. """
+    ref_date::Array = [Dates.DateTime(0)]
+    """ Whether the callback is active. """
+    active::Bool = false
+    """ Data to be passed to the callback function. """
+    data::Array = []
 end
 
 """
-    strdate_to_datetime(strdate::String)
+    dt_cb(cb::HourlyCallback)
+    dt_cb(cb::MonthlyCallback)
 
-Convert from String ("YYYYMMDD") to Date format,
-required by the official AMIP input files.
+This function returns the time interval for the callback.
 """
-strdate_to_datetime(strdate::String) = Dates.DateTime(
-    parse(Int, strdate[1:4]),
-    parse(Int, strdate[5:6]),
-    parse(Int, strdate[7:8]),
-)
+dt_cb(cb::HourlyCallback) = Dates.Hour(cb.dt)
+dt_cb(cb::MonthlyCallback) = Dates.Month(cb.dt)
 
-"""
-    datetime_to_strdate(datetime::Dates.DateTime)
 
-Convert from DateTime to String ("YYYYMMDD") format.
 """
-datetime_to_strdate(datetime::Dates.DateTime) =
-    string(lpad(Dates.year(datetime), 4, "0")) *
-    string(string(lpad(Dates.month(datetime), 2, "0"))) *
-    string(lpad(Dates.day(datetime), 2, "0"))
+    AbstractFrequency
 
+This is an abstract type for the frequency of a callback function.
+"""
 abstract type AbstractFrequency end
 struct Monthly <: AbstractFrequency end
 struct EveryTimestep <: AbstractFrequency end
@@ -105,4 +112,56 @@ function trigger_callback(
     end
 end
 
+"""
+    to_datetime(date)
+
+Convert a `DateTime`-like object (e.g. `DateTimeNoLeap`) to a `DateTime`.
+We need this since some data files we use contain
+`DateTimeNoLeap` objects for dates, which can't be used for math with `DateTime`s.
+The `DateTimeNoLeap` type uses the Gregorian calendar without leap years, while
+the `DateTime` type uses Gregorian calendar with leap years.
+
+For consistency, all input data files should have dates converted to `DateTime`
+before being used in a simulation.
+
+This function is similar to `reinterpret` in CFTime.jl.
+
+# Arguments
+- `date`: `DateTime`-like object to be converted to `DateTime`
+"""
+function to_datetime(date)
+    return Dates.DateTime(
+        Dates.year(date),
+        Dates.month(date),
+        Dates.day(date),
+        Dates.hour(date),
+        Dates.minute(date),
+        Dates.second(date),
+        Dates.millisecond(date),
+    )
+end
+
+"""
+    strdate_to_datetime(strdate::String)
+
+Convert from String ("YYYYMMDD") to Date format,
+required by the official AMIP input files.
+"""
+strdate_to_datetime(strdate::String) = Dates.DateTime(
+    parse(Int, strdate[1:4]),
+    parse(Int, strdate[5:6]),
+    parse(Int, strdate[7:8]),
+)
+
+"""
+    datetime_to_strdate(datetime::Dates.DateTime)
+
+Convert from DateTime to String ("YYYYMMDD") format.
+"""
+datetime_to_strdate(datetime::Dates.DateTime) =
+    string(lpad(Dates.year(datetime), 4, "0")) *
+    string(string(lpad(Dates.month(datetime), 2, "0"))) *
+    string(lpad(Dates.day(datetime), 2, "0"))
+
+
 end # module CallbackManager