--- a/weather_server/common.py	Sun Sep 29 20:42:11 2019 -0400
+++ b/weather_server/common.py	Sun Oct 06 13:11:11 2019 -0400
@@ -1,3 +1,5 @@
+import datetime
+import json
 import typing as t
 
 import bson
@@ -9,3 +11,22 @@
 
 def bson_encode(data: t.Dict[str, t.Any]) -> bytes:
     return bson.BSON.encode(data, codec_options=BSON_OPTIONS)
+
+
+class DateEncoder(json.JSONEncoder):
+
+    def default(self, o: t.Any) -> t.Any:
+        if not isinstance(o, datetime.datetime):
+            return super().default(o)
+        return o.timestamp()
+
+
+JSON_ENCODER = DateEncoder(sort_keys=True)
+
+
+def json_dumps(data: t.Any) -> str:
+    return JSON_ENCODER.encode(data)
+
+
+def utc_now():
+    return datetime.datetime.utcnow().replace(tzinfo=pytz.UTC)