diff --git a/src/actions/recomputeReduxState.js b/src/actions/recomputeReduxState.js
index cdda54227..7accd1dd1 100644
--- a/src/actions/recomputeReduxState.js
+++ b/src/actions/recomputeReduxState.js
@@ -10,6 +10,7 @@ import { getDefaultFrequenciesState } from "../reducers/frequencies";
 import { countTraitsAcrossTree, calcTotalTipsInTree } from "../util/treeCountingHelpers";
 import { calcEntropyInView } from "../util/entropy";
 import { treeJsonToState } from "../util/treeJsonProcessing";
+import { castIncorrectTypes } from "../util/castJsonTypes";
 import { entropyCreateState } from "../util/entropyCreateStateFromJsons";
 import { determineColorByGenotypeMutType, calcNodeColor } from "../util/colorHelpers";
 import { calcColorScale, createVisibleLegendValues } from "../util/colorScale";
@@ -768,11 +769,13 @@ export const createStateFromQueryOrJSONs = ({
     frequencies = getDefaultFrequenciesState();
     /* new tree state(s) */
     tree = treeJsonToState(json.tree);
+    castIncorrectTypes(metadata, tree);
     tree.debug = "LEFT";
     tree.name = mainTreeName;
     metadata.mainTreeNumTips = calcTotalTipsInTree(tree.nodes);
     if (secondTreeDataset) {
       treeToo = treeJsonToState(secondTreeDataset.tree);
+      castIncorrectTypes(metadata, treeToo);
       treeToo.debug = "RIGHT";
       treeToo.name = secondTreeName;
       /* TODO: calc & display num tips in 2nd tree */
diff --git a/src/util/castJsonTypes.js b/src/util/castJsonTypes.js
new file mode 100644
index 000000000..a792bed5e
--- /dev/null
+++ b/src/util/castJsonTypes.js
@@ -0,0 +1,37 @@
+/**
+ * Values in the JSON should be appropriately typed however this may not always be the case.
+ * For instance, certain values of a continuous trait may be strings, and we should cast
+ * these to numbers. See https://github.com/nextstrain/auspice/issues/1626 for more discussion
+ * of this particular case. Feel free to add more checks / casts to this function!
+ * @param {Object} metadata
+ * @param {Object} tree
+ * @returns {undefined} Any type casting is in-place
+ */
+export const castIncorrectTypes = (metadata, tree) => {
+  try {
+    const continuousKeys = new Set();
+    Object.entries(metadata.colorings || {}).forEach(([key, details]) => {
+      if (details.type==="continuous") {
+        continuousKeys.add(key);
+      }
+    });
+    tree.nodes.forEach((node) => {
+      Object.entries(node.node_attrs || {}).forEach(([key, details]) => {
+        if (continuousKeys.has(key)) {
+          if ((typeof details.value) !== "number") {
+            if (details.value==="" || isNaN(details.value)) { // Note: Number("")=0
+              // undefined values are handled appropriately (e.g. scatterplots, tooltips etc)
+              details.value = undefined;
+            } else {
+              details.value = Number(details.value);
+            }
+          }
+        }
+      });
+    });
+  } catch (err) {
+    // type casting shouldn't be required (the JSON should be correctly typed)
+    // so any errors shouldn't prevent Auspice loading
+    console.error(err);
+  }
+};