diff --git a/exploration/whole_hist_viz.py b/exploration/whole_hist_viz.py
new file mode 100755
index 0000000..5b578b7
--- /dev/null
+++ b/exploration/whole_hist_viz.py
@@ -0,0 +1,131 @@
+import argparse
+import datetime
+
+import polars as pl
+from plotnine import aes, geom_line, ggplot, theme_bw
+
+
+def make_plot(dfp, ignore_under, first_date, last_date):
+    r"""
+    Plots all NextStrain clades in the available data, weekly, for the full duration.
+    """
+
+    lineage_year = (
+        pl.col("lineage")
+        .replace("recombinant", "0")
+        .str.extract(r"(\d+)")
+        .str.to_integer(strict=True)
+        .add(2000)
+    )
+
+    df = (
+        pl.scan_csv(dfp, separator="\t")
+        .rename({"clade_nextstrain": "lineage"})
+        .cast({"date": pl.Date, "date_submitted": pl.Date}, strict=False)
+        .filter(
+            pl.col("lineage").is_not_null(),
+            # Drop samples with missing collection or reporting dates
+            pl.col("date").is_not_null(),
+            # Drop samples claiming to be reported before being collected
+            pl.col("date") <= pl.col("date_submitted"),
+            # Keep only samples in range of specified days
+            pl.col("date") >= first_date,
+            pl.col("date") <= last_date,
+            # Drop impossible lineage assigments
+            # (lineages which had not yet been named, e.g. a sequence
+            # in 2020 cannot belong to 23D)
+            pl.col("date").dt.year() >= lineage_year,
+            country="USA",
+            host="Homo sapiens",
+        )
+    )
+
+    df = (
+        df.with_columns(wd=pl.col("date").dt.weekday())
+        .with_columns(
+            offset=pl.col("wd").map_elements(
+                lambda x: "-" + str(x) + "d" if x != 7 else "0d",
+                return_dtype=pl.String,
+            )
+        )
+        .with_columns(pl.col("date").dt.offset_by(pl.col("offset")))
+        .group_by("lineage", "date")
+        .agg(pl.len().alias("count"))
+        .with_columns(
+            frequency=(pl.col("count") / pl.sum("count").over("date")),
+        )
+        .select("date", "lineage", "frequency")
+        .collect()
+    )
+
+    trivial = (
+        df.group_by("lineage")
+        .agg(pl.col("frequency").max())
+        .with_columns(ignorable=(pl.col("frequency") < ignore_under))
+    )
+
+    plt = (
+        ggplot(
+            df.join(
+                trivial.drop("frequency"), on="lineage", how="left"
+            ).filter(pl.col("ignorable").not_())
+        )
+        + geom_line(
+            aes(
+                x="date",
+                y="frequency",
+                color="lineage",
+            ),
+        )
+        + theme_bw()
+    )
+
+    return plt
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="A simple plot of the proportions of all currently-named NextStrain clades over time in the United States, with no per-state breakdown."
+    )
+    parser.add_argument("data_filename")
+    parser.add_argument("output_filepath")
+    parser.add_argument(
+        "-f",
+        "--first_date",
+        default="1900-01-01",
+        help="Plot will only include data for this day or later. Default corresponds to all days.",
+    )
+    parser.add_argument(
+        "-l",
+        "--last_date",
+        default="2100-01-01",
+        help="Plot will only include data for up to this day or earlier. Default corresponds to all days.",
+    )
+    parser.add_argument(
+        "-c",
+        "--frequency_cutoff",
+        default=0.5,
+        help="Plot will only include lineages which exceed this frequency in at least one week",
+    )
+    parser.add_argument(
+        "-w", "--width", default=6, help="Plot width, in inches."
+    )
+    parser.add_argument(
+        "-t", "--height", default=4, help="Plot height, in inches."
+    )
+
+    args = parser.parse_args()
+
+    plt = make_plot(
+        args.data_filename,
+        ignore_under=float(args.frequency_cutoff),
+        first_date=datetime.datetime.strptime(args.first_date, "%Y-%m-%d"),
+        last_date=datetime.datetime.strptime(args.last_date, "%Y-%m-%d"),
+    )
+
+    plt.save(
+        args.output_filepath,
+        width=float(args.width),
+        height=float(args.height),
+        limitsize=False,
+    )
diff --git a/linmod/data.py b/linmod/data.py
index 368cadb..cb6e139 100755
--- a/linmod/data.py
+++ b/linmod/data.py
@@ -132,6 +132,7 @@
 `data` key.
 """
 
+
 if __name__ == "__main__":
     # Load configuration, if given
 
@@ -192,6 +193,14 @@
         f'{config["data"]["horizon"]["upper"]}d'
     )
 
+    lineage_year = (
+        pl.col("lineage")
+        .replace("recombinant", "0")
+        .str.extract(r"(\d+)")
+        .str.to_integer(strict=True)
+        .add(2000)
+    )
+
     full_df = (
         pl.scan_csv(cache_path, separator="\t")
         .rename({config["data"]["lineage_column_name"]: "lineage"})
@@ -200,6 +209,8 @@
         # that are resolved only to the month, not the day
         .cast({"date": pl.Date, "date_submitted": pl.Date}, strict=False)
         .filter(
+            # Drop samples with missing lineage
+            pl.col("lineage").is_not_null(),
             # Drop samples with missing collection or reporting dates
             pl.col("date").is_not_null(),
             pl.col("date_submitted").is_not_null(),
@@ -208,6 +219,10 @@
             pl.col("date") <= horizon_upper_date,
             # Drop samples claiming to be reported before being collected
             pl.col("date") <= pl.col("date_submitted"),
+            # Drop impossible lineage assigments
+            # (lineages which had not yet been named, e.g. a sequence
+            # in 2020 cannot belong to 23D)
+            pl.col("date").dt.year() >= lineage_year,
             # Drop samples not from humans in the included US divisions
             pl.col("division").is_in(config["data"]["included_divisions"]),
             country="USA",