diff --git a/sopel/modules/isup.py b/sopel/modules/isup.py
index afb6049b17..f2f1bfe8a5 100644
--- a/sopel/modules/isup.py
+++ b/sopel/modules/isup.py
@@ -60,22 +60,33 @@ def handle_isup(bot, trigger, secure=True):
     """
     try:
         site = get_site_url(trigger.group(2))
-        response = requests.head(site, verify=secure)
+        response = requests.head(site, verify=secure, timeout=(10.0, 5.0))
         response.raise_for_status()
-        response = response.headers
     except ValueError as error:
         bot.reply(str(error))
     except requests.exceptions.SSLError:
         bot.say(
-            '%s looks down from here. Try using %sisupinsecure'
-            % (site, bot.config.core.help_prefix))
-    except requests.RequestException:
-        bot.say('%s looks down from here.' % site)
-    else:
-        if response:
-            bot.say(site + ' looks fine to me.')
-        else:
-            bot.say(site + ' is down from here.')
+            '{} looks down to me (SSL error). Try using `{}isupinsecure`.'
+            .format(site, bot.config.core.help_prefix))
+    except requests.HTTPError:
+        bot.say(
+            '{} looks down to me (HTTP {} "{}").'
+            .format(site, response.status_code, response.reason))
+    except requests.ConnectTimeout:
+        bot.say(
+            '{} looks down to me (timed out while connecting).'
+            .format(site))
+    except requests.ReadTimeout:
+        bot.say(
+            '{} looks down to me (timed out waiting for reply).'
+            .format(site))
+    except requests.ConnectionError:
+        bot.say(
+            '{} looks down to me (connection error).'
+            .format(site))
+
+    # If no exception happened, the request succeeded.
+    bot.say(site + ' looks fine to me.')
 
 
 @plugin.command('isupinsecure')
diff --git a/test/modules/test_modules_isup.py b/test/modules/test_modules_isup.py
index 2241c8ea80..5ec854d641 100644
--- a/test/modules/test_modules_isup.py
+++ b/test/modules/test_modules_isup.py
@@ -31,6 +31,7 @@ def test_get_site_url(site, expected):
 
 
 INVALID_SITE_URLS = (
+    None,  # missing
     '',  # empty
     '      ',  # empty once stripped
     'steam://browsemedia',  # invalid protocol