diff --git a/NEWS.md b/NEWS.md
index a6dea9a..1c0c032 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -17,6 +17,20 @@
 - The run-title caption wraps long tokens (e.g. commit hashes) and renders
   newlines as line breaks
 
+### Bug fixes
+
+- `aggregate_var` now implements the `:monthly` and `:daily` levels that
+  `available_levels` advertises for sub-monthly-native data (previously it
+  threw "Unknown aggregation level: monthly", which crashed the server during
+  precompute for e.g. a daily `pr` output with a registered observation)
+- Coupled-mode `precompute_dashboard_cache` now uses the component's own
+  `SimDir` (pruned to monthly, read from `output_active`) instead of
+  re-scanning the raw component folder — it no longer trips over stale loose
+  files ("Time dimension is not in non-decreasing order") or precomputes
+  entries the UI never serves, and its fingerprints match runtime lookups
+- Precompute failures on a single cache entry are warned and skipped instead
+  of aborting server startup
+
 #### ClimaCoupler (multi-component) outputs
 - `dashboard(path; coupled = true)` reads ClimaCoupler output directories
   (`clima_atmos/`, `clima_land/`, `clima_ocean/`, `clima_seaice/` subfolders)
diff --git a/docs/src/api.md b/docs/src/api.md
index 2939ba1..9f46025 100644
--- a/docs/src/api.md
+++ b/docs/src/api.md
@@ -20,6 +20,12 @@ default_inversion_obs
 default_gpcp_obs
 ```
 
+## Display units
+
+```@docs
+to_display_units
+```
+
 ## Index
 
 ```@index
diff --git a/src/benchmark.jl b/src/benchmark.jl
index 7a8689b..008227c 100644
--- a/src/benchmark.jl
+++ b/src/benchmark.jl
@@ -390,6 +390,10 @@ function aggregation_label(var, level)
         return "Seasonal"
     elseif level == :annual
         return "Annual"
+    elseif level == :monthly
+        return "Monthly"
+    elseif level == :daily
+        return "Daily"
     else
         return string(level)
     end
@@ -431,6 +435,8 @@ averaging is NaN-aware. `level == :native` returns `var` unchanged.
   new time coordinate).
 - `:seasonal`: one frame per (year, season) bin, in chronological order. Season
   is defined by month: DJF, MAM, JJA, SON. DJF is keyed to the year of January.
+- `:monthly`: one frame per (year, month) bin (for daily/hourly-native data).
+- `:daily`: one frame per calendar day (for hourly-native data).
 """
 function aggregate_var(var, level::Symbol)
     level == :native && return var
@@ -453,6 +459,18 @@ function aggregate_var(var, level::Symbol)
         groups = [findall(==(k), keys_per_date) for k in unique_keys]
         new_times = [times[g[(length(g)+1)÷2]] for g in groups]
         return _aggregate_by_groups(var, groups, new_times)
+    elseif level == :monthly
+        keys_per_date = map(d -> (Dates.year(d), Dates.month(d)), dates)
+        unique_keys = sort!(unique(keys_per_date))
+        groups = [findall(==(k), keys_per_date) for k in unique_keys]
+        new_times = [times[g[(length(g)+1)÷2]] for g in groups]
+        return _aggregate_by_groups(var, groups, new_times)
+    elseif level == :daily
+        keys_per_date = map(d -> Dates.Date(d), dates)
+        unique_keys = sort!(unique(keys_per_date))
+        groups = [findall(==(k), keys_per_date) for k in unique_keys]
+        new_times = [times[g[(length(g)+1)÷2]] for g in groups]
+        return _aggregate_by_groups(var, groups, new_times)
     else
         error("Unknown aggregation level: $level")
     end
diff --git a/src/cache.jl b/src/cache.jl
index a99b9f5..87c34e1 100644
--- a/src/cache.jl
+++ b/src/cache.jl
@@ -233,7 +233,7 @@ end
 # ─── Batch precompute ─────────────────────────────────────────────────────────
 
 """
-    precompute_dashboard_cache(path; obs = default_era5_obs(), verbose = true, mask_kind = :land)
+    precompute_dashboard_cache(path; obs = default_obs(), verbose = true, mask_kind = :land, simdir = ClimaAnalysis.SimDir(path))
 
 Warm the persistent benchmark cache for every (variable, reduction, period,
 aggregation level) in `path` that has a registered observation. Already-cached,
@@ -244,14 +244,26 @@ re-run — e.g. after regenerating the longrun, or on each server restart.
 `:land` (ocean-masked, the default), `:globe` (atmos components of coupled
 runs) or `:ocean`. It must match what the dashboard will use for this output.
 
+Pass `simdir` when the dashboard will serve a filtered/relocated view of
+`path` (e.g. a coupled component pruned to monthly diagnostics and read from
+`output_active`, see `discover_components`) — precomputing from a different
+`SimDir` than the dashboard uses would both cover entries the UI never shows
+and produce fingerprints that never match at lookup time. The cache still
+lives at `<path>/.climaviz_cache`.
+
 Run this once after producing the simulation output (or in CI). The dashboard
 reads whatever is present and falls back to live computation on a miss, so
 precomputing is purely a responsiveness optimization.
 
 Returns the `BenchmarkCache`.
 """
-function precompute_dashboard_cache(path; obs = default_obs(), verbose = true, mask_kind::Symbol = :land)
-    simdir = ClimaAnalysis.SimDir(path)
+function precompute_dashboard_cache(
+    path;
+    obs = default_obs(),
+    verbose = true,
+    mask_kind::Symbol = :land,
+    simdir = ClimaAnalysis.SimDir(path),
+)
     cache = BenchmarkCache(path; enabled = true)
     if isnothing(cache.dir)
         @warn "ClimaViz: cache directory unavailable; nothing precomputed" path
@@ -282,13 +294,20 @@ function precompute_dashboard_cache(path; obs = default_obs(), verbose = true, m
                         verbose && @info "  skip (up-to-date)" var = short_name reduction period level
                         continue
                     end
-                    obs_agg = aggregate_obs(o, var, level)
-                    isnothing(obs_agg) && continue
-                    sim_agg = aggregate_var(var, level)
-                    entry = compute_benchmark_entry(sim_agg, obs_agg, fingerprint; mask = mask_spec(mask_kind).mask)
-                    put_cached_entry!(cache, key, entry)
-                    n_done += 1
-                    verbose && @info "  cached" var = short_name reduction period level n = entry.n
+                    # Precompute is an optimization: one bad entry must never
+                    # take the server down (the dashboard falls back to live
+                    # computation on a miss), so failures are warned and skipped.
+                    try
+                        obs_agg = aggregate_obs(o, var, level)
+                        isnothing(obs_agg) && continue
+                        sim_agg = aggregate_var(var, level)
+                        entry = compute_benchmark_entry(sim_agg, obs_agg, fingerprint; mask = mask_spec(mask_kind).mask)
+                        put_cached_entry!(cache, key, entry)
+                        n_done += 1
+                        verbose && @info "  cached" var = short_name reduction period level n = entry.n
+                    catch e
+                        @warn "ClimaViz: skip $short_name/$reduction/$period/$level (compute failed)" exception = (e, catch_backtrace())
+                    end
                 end
             end
         end
diff --git a/src/dashboard.jl b/src/dashboard.jl
index 6449df4..ab6fd67 100644
--- a/src/dashboard.jl
+++ b/src/dashboard.jl
@@ -98,7 +98,10 @@ function dashboard(path; HPC = false, obs = default_obs(), cache = true, precomp
         if precompute && cache
             for c in components_found
                 kind = component_mask_kind(c.label)
-                precompute_dashboard_cache(c.path; obs = obs, mask_kind = kind)
+                # Pass the component's SimDir (pruned, read from output_active)
+                # so precompute covers exactly what the UI serves and its
+                # fingerprints match the runtime lookups.
+                precompute_dashboard_cache(c.path; obs = obs, mask_kind = kind, simdir = c.simdir)
                 precompute_summary!(
                     c.simdir, components[c.label].bench_cache, obs;
                     fallback_start_date = coupled_fallback_start_date, mask_kind = kind,
diff --git a/test/test_benchmark.jl b/test/test_benchmark.jl
index dd9644f..bae8999 100644
--- a/test/test_benchmark.jl
+++ b/test/test_benchmark.jl
@@ -74,4 +74,42 @@
             @test haskey(obs, name)
         end
     end
+
+    @testset "aggregate_var monthly/daily (sub-monthly native data)" begin
+        # Daily var spanning a month boundary: Jan 30, Jan 31, Feb 1, Feb 2.
+        daily = ClimaAnalysis.OutputVar(
+            Dict{String, Any}(
+                "short_name" => "pr", "units" => "mm day^-1",
+                "start_date" => "2000-01-30T00:00:00",
+            ),
+            Dict("time" => [0.0, 1.0, 2.0, 3.0] .* 86400.0),
+            Dict{String, Dict}(),
+            [1.0, 2.0, 3.0, 4.0],
+        )
+        monthly = ClimaViz.aggregate_var(daily, :monthly)
+        @test length(monthly.dims["time"]) == 2
+        @test vec(monthly.data) ≈ [1.5, 3.5]
+
+        # Hourly var spanning a day boundary: 23:00 Jan 1, then 00:00/01:00 Jan 2.
+        hourly = ClimaAnalysis.OutputVar(
+            Dict{String, Any}(
+                "short_name" => "pr", "units" => "mm day^-1",
+                "start_date" => "2000-01-01T23:00:00",
+            ),
+            Dict("time" => [0.0, 1.0, 2.0] .* 3600.0),
+            Dict{String, Dict}(),
+            [1.0, 3.0, 5.0],
+        )
+        by_day = ClimaViz.aggregate_var(hourly, :daily)
+        @test length(by_day.dims["time"]) == 2
+        @test vec(by_day.data) ≈ [1.0, 4.0]
+
+        # Regression: every advertised level must aggregate without throwing
+        # (a daily var advertises :monthly, which used to error and could take
+        # the whole precompute down).
+        for level in ClimaViz.available_levels(daily)
+            agg = ClimaViz.aggregate_var(daily, level)
+            @test agg isa ClimaAnalysis.OutputVar
+        end
+    end
 end