diff --git a/src/bin/home.rs b/src/bin/home.rs
index 6a5b29a..caac55a 100644
--- a/src/bin/home.rs
+++ b/src/bin/home.rs
@@ -25,8 +25,8 @@ fn main() {
     // Realtime upload/download rate for a interface
     bar.push(NetworkSpeedWidget::new(&opts.nic, 6));
 
-    let mut dt = DateTimeWidget::new("%m/%d %H:%M".to_string());
-    dt.set_colors(&vec![
+    let mut dt = DateTimeWidget::new("%m/%d %H:%M");
+    dt.set_colors(vec![
         TimeColor {
             start: NaiveTime::from_hms(19, 0, 0),
             color: ColorRGB::yellow(),
diff --git a/src/bin/work.rs b/src/bin/work.rs
index 184f772..c8a5074 100644
--- a/src/bin/work.rs
+++ b/src/bin/work.rs
@@ -25,8 +25,8 @@ fn main() {
     // Realtime upload/download rate for a interface
     bar.push(NetworkSpeedWidget::new(&opts.nic, 6));
 
-    let mut dt = DateTimeWidget::tz("%H:%M %Z".to_string(), "Europe/London".to_string());
-    dt.set_colors(&vec![
+    let mut dt = DateTimeWidget::tz("%H:%M %Z", chrono_tz::Europe::London);
+    dt.set_colors(vec![
         TimeColor {
             start: NaiveTime::from_hms(0, 0, 0),
             color: ColorRGB::red(),
@@ -46,8 +46,8 @@ fn main() {
     ]);
     bar.push(dt);
 
-    let mut dt = DateTimeWidget::new("%m/%d %H:%M".to_string());
-    dt.set_colors(&vec![
+    let mut dt = DateTimeWidget::new("%m/%d %H:%M");
+    dt.set_colors(vec![
         TimeColor {
             start: NaiveTime::from_hms(0, 0, 0),
             color: ColorRGB::red(),
diff --git a/src/widgets/datetime.rs b/src/widgets/datetime.rs
index 7e899e8..4d1a25e 100644
--- a/src/widgets/datetime.rs
+++ b/src/widgets/datetime.rs
@@ -1,19 +1,17 @@
-use chrono::NaiveTime;
-use chrono_tz::Tz;
+use chrono::{offset::TimeZone, Local, NaiveTime, Utc};
+use std::fmt::Display;
 
 use i3monkit::Block;
 use i3monkit::ColorRGB;
 use i3monkit::{Widget, WidgetUpdate};
 
 /// The widget that shows local time
-pub struct DateTimeWidget {
+pub struct DateTimeWidget<Tz> {
     /// fmt to format the datetime, see
     /// https://docs.rs/chrono/*/chrono/format/strftime/index.html for documentation.
     fmt: String,
-    /// tz string, values from https://docs.rs/chrono-tz/*/chrono_tz/
-    /// None will use local time.
-    tz: Option<String>,
-    colors: Option<Vec<TimeColor>>,
+    tz: Tz,
+    colors: Vec<TimeColor>,
 }
 
 #[derive(Clone)]
@@ -22,66 +20,63 @@ pub struct TimeColor {
     pub color: ColorRGB,
 }
 
-impl DateTimeWidget {
-    // Create a new time widget
-    pub fn new(fmt: String) -> Self {
-        DateTimeWidget {
-            fmt,
-            tz: None,
-            colors: None,
-        }
-    }
-    pub fn tz(fmt: String, tz: String) -> Self {
-        DateTimeWidget {
-            fmt,
-            tz: Some(tz),
-            colors: None,
-        }
-    }
-    pub fn set_colors(&mut self, colors: &[TimeColor]) {
-        let mut colors = colors.to_vec();
-        colors.sort_by(|l, r| l.start.cmp(&r.start));
-        self.colors = Some(colors);
+impl DateTimeWidget<Local> {
+    pub fn new(fmt: impl Into<String>) -> Self {
+        DateTimeWidget::tz(fmt, Local)
     }
 }
 
-impl Widget for DateTimeWidget {
+impl<Tz> DateTimeWidget<Tz>
+where
+    Tz: TimeZone,
+    Tz::Offset: Display,
+{
+    pub fn tz(fmt: impl Into<String>, tz: Tz) -> Self {
+        DateTimeWidget {
+            fmt: fmt.into(),
+            tz,
+            colors: Vec::new(),
+        }
+    }
+    pub fn set_colors(&mut self, colors: impl Into<Vec<TimeColor>>) {
+        let mut colors = colors.into();
+        colors.sort_by(|l, r| l.start.cmp(&r.start));
+        self.colors = colors;
+    }
+    fn now(&self) -> chrono::DateTime<Tz> {
+        Utc::now().with_timezone(&self.tz)
+    }
+}
+
+impl<Tz> Widget for DateTimeWidget<Tz>
+where
+    Tz: TimeZone,
+    Tz::Offset: Display,
+{
     fn update(&mut self) -> Option<WidgetUpdate> {
-        let (time, time_string) = match &self.tz {
-            Some(tz) => {
-                let tz: Tz = tz.parse().unwrap();
-                let now = chrono::Local::now();
-                let now = now.with_timezone(&tz);
-                (now.time(), now.format(&self.fmt).to_string())
-            }
-            None => {
-                let now = chrono::Local::now();
-                (now.time(), now.format(&self.fmt).to_string())
-            }
-        };
-        let color = if let Some(colors) = &self.colors {
-            colors
-                .iter()
-                .filter(|tc| tc.start < time)
-                .last()
-                .map(|tc| tc.color.clone())
-        } else {
-            None
-        };
+        let now = self.now();
 
         let time_string = format!(
             r#"<span size="x-large" weight="heavy">{}</span>"#,
-            time_string
+            now.format(&self.fmt)
         );
         let mut data = Block::new()
             .append_full_text(&time_string)
             .use_pango()
             .clone();
-        if let Some(color) = color {
+
+        let time = now.time();
+        if let Some(color) = self
+            .colors
+            .iter()
+            .filter(|tc| tc.start < time)
+            .last()
+            .map(|tc| tc.color.clone())
+        {
             data.color(color);
         }
         Some(WidgetUpdate {
-            refresh_interval: std::time::Duration::new(1, 0),
+            refresh_interval: std::time::Duration::from_secs(1),
             data: Some(data),
         })
     }