diff --git a/src/database.py b/src/database.py
index 51be1c6..973e81f 100644
--- a/src/database.py
+++ b/src/database.py
@@ -40,7 +40,7 @@
     convert_forecasts_to_many_datetime_many_generation,
     convert_location_sql_to_many_datetime_many_generation,
 )
-from utils import floor_30_minutes_dt, get_start_datetime
+from utils import floor_30_minutes_dt, get_start_datetime, filter_forecast_values
 
 logger = structlog.stdlib.get_logger()
 
@@ -122,14 +122,19 @@ def get_forecasts_from_database(
 
     else:
         # To speed up read time we only look at the last 12 hours of results, and take floor 30 mins
-        yesterday_start_datetime = floor_30_minutes_dt(
-            datetime.now(tz=timezone.utc) - timedelta(hours=12)
-        )
+        if start_datetime_utc is None:
+            start_datetime_utc = floor_30_minutes_dt(
+                datetime.now(tz=timezone.utc) - timedelta(hours=12)
+            )
+
+        start_created_utc = floor_30_minutes_dt(
+                datetime.now(tz=timezone.utc) - timedelta(hours=12)
+            )
 
         forecasts = get_all_gsp_ids_latest_forecast(
             session=session,
-            start_created_utc=yesterday_start_datetime,
-            start_target_time=yesterday_start_datetime,
+            start_created_utc=start_created_utc,
+            start_target_time=start_datetime_utc,
             preload_children=True,
             model_name="blend",
             end_target_time=end_datetime_utc,
@@ -137,7 +142,7 @@ def get_forecasts_from_database(
 
     if compact:
         return convert_forecasts_to_many_datetime_many_generation(
-            forecasts=forecasts, historic=historic
+            forecasts=forecasts, historic=historic, start_datetime_utc=start_datetime_utc, end_datetime_utc=end_datetime_utc
         )
 
     else:
@@ -147,6 +152,8 @@ def get_forecasts_from_database(
         else:
             forecasts = [Forecast.from_orm(forecast) for forecast in forecasts]
 
+        forecasts = filter_forecast_values(end_datetime_utc, forecasts, start_datetime_utc)
+
         # return as many forecasts
         return ManyForecasts(forecasts=forecasts)
 
diff --git a/src/utils.py b/src/utils.py
index 4bc737c..41a31d6 100644
--- a/src/utils.py
+++ b/src/utils.py
@@ -1,14 +1,16 @@
 """ Utils functions for main.py """
 import os
 from datetime import datetime, timedelta
-from typing import Optional, Union
+from typing import List, Optional, Union
 
 import numpy as np
 import structlog
-from nowcasting_datamodel.models import ForecastValue
+from nowcasting_datamodel.models import ForecastValue, ForecastSQL
 from pydantic import Field
 from pytz import timezone
 
+from database import logger
+
 logger = structlog.stdlib.get_logger()
 
 europe_london_tz = timezone("Europe/London")
@@ -71,9 +73,10 @@ def format_datetime(datetime_str: str = None):
     else:
         datetime_output = datetime.fromisoformat(datetime_str)
         if datetime_output.tzinfo is None:
-            datetime_output = europe_london_tz.localize(datetime_output)
+            datetime_output = utc.localize(datetime_output)
         return datetime_output
 
+
 def get_start_datetime(
     n_history_days: Optional[Union[str, int]] = None, start_datetime: Optional[datetime] = None
 ) -> datetime:
@@ -92,10 +95,7 @@ def get_start_datetime(
 
     now = datetime.now(tz=utc)
 
-    if (
-        start_datetime is None
-        or now - start_datetime > timedelta(days=3)
-    ):
+    if start_datetime is None or now - start_datetime > timedelta(days=3):
         if n_history_days is None:
             n_history_days = os.getenv("N_HISTORY_DAYS", "yesterday")
 
@@ -174,3 +174,40 @@ def format_plevels(national_forecast_value: NationalForecastValue):
         national_forecast_value.plevels["plevel_90"] = (
             national_forecast_value.expected_power_generation_megawatts * 1.2
         )
+
+
+def filter_forecast_values(
+    forecasts: List[ForecastSQL],
+    end_datetime_utc: Optional[datetime] = None,
+    start_datetime_utc: Optional[datetime] = None,
+) -> List[ForecastSQL]:
+    """
+    Filter forecast values by start and end datetime
+
+    :param forecasts: list of forecasts
+    :param end_datetime_utc: start datetime
+    :param start_datetime_utc: e
+    :return:
+    """
+    if start_datetime_utc is not None or end_datetime_utc is not None:
+        logger.info(f"Filtering forecasts from {start_datetime_utc} to {end_datetime_utc}")
+        forecasts_filtered = []
+        for forecast in forecasts:
+            forecast_values = forecast.forecast_values
+            if start_datetime_utc is not None:
+                forecast_values = [
+                    forecast_value
+                    for forecast_value in forecast_values
+                    if forecast_value.target_time >= start_datetime_utc
+                ]
+            if end_datetime_utc is not None:
+                forecast_values = [
+                    forecast_value
+                    for forecast_value in forecast_values
+                    if forecast_value.target_time <= end_datetime_utc
+                ]
+            forecast.forecast_values = forecast_values
+
+            forecasts_filtered.append(forecast)
+        forecasts = forecasts_filtered
+    return forecasts