diff --git a/.github/workflows/build-test.yml b/.github/workflows/build-test.yml
index 31eb3437351..1891ed1aad9 100644
--- a/.github/workflows/build-test.yml
+++ b/.github/workflows/build-test.yml
@@ -18,6 +18,19 @@ on:
     branches: [ main ]
   pull_request:
     branches: '*'
+  workflow_dispatch:
+    inputs:
+      nightly:
+        description: "Test on latest nightly"
+        required: true
+        default: false
+        type: boolean
+  schedule:
+    # Run nightly cronjob CI every day at 14 UTC / 6AM PST / 3PM CET
+    - cron:  '0 14 * * *'
+
+env:
+  INSTALLED_NIGHTLY_VERSION: nightly-2022-04-05
 
 jobs:
 
@@ -26,6 +39,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
 
@@ -65,6 +85,13 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
     - name: Get cargo-make version
@@ -100,6 +127,13 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
     - name: Get cargo-make version
@@ -145,6 +179,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
     - name: Get cargo-make version
@@ -177,6 +218,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
     - name: Attempt to load cached CLDR source data
@@ -227,17 +275,24 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
 
     - name: Load cortex target for no_std build.
       run: |
-        rustup install nightly-2022-04-05
-        rustup component add --toolchain nightly-2022-04-05 rust-src
-        rustup target add thumbv7m-none-eabi --toolchain nightly-2022-04-05
-        rustup target add thumbv8m.main-none-eabihf --toolchain nightly-2022-04-05
-        rustup target add x86_64-unknown-linux-gnu --toolchain nightly-2022-04-05
-        rustup target add wasm32-unknown-unknown --toolchain nightly-2022-04-05
+        rustup install $INSTALLED_NIGHTLY_VERSION
+        rustup component add --toolchain $INSTALLED_NIGHTLY_VERSION rust-src
+        rustup target add thumbv7m-none-eabi --toolchain $INSTALLED_NIGHTLY_VERSION
+        rustup target add thumbv8m.main-none-eabihf --toolchain $INSTALLED_NIGHTLY_VERSION
+        rustup target add x86_64-unknown-linux-gnu --toolchain $INSTALLED_NIGHTLY_VERSION
+        rustup target add wasm32-unknown-unknown --toolchain $INSTALLED_NIGHTLY_VERSION
 
     - name: Set up Clang-14
       run: |
@@ -291,6 +346,13 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
     - name: Load nightly for rustdoc-json
@@ -363,6 +425,13 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
 
@@ -388,9 +457,9 @@ jobs:
 
     - name: Load wasi for gn.
       run: |
-        rustup install nightly-2022-04-05
-        rustup component add --toolchain nightly-2022-04-05 rust-src
-        rustup target add wasm32-wasi --toolchain nightly-2022-04-05
+        rustup install $INSTALLED_NIGHTLY_VERSION
+        rustup component add --toolchain $INSTALLED_NIGHTLY_VERSION rust-src
+        rustup target add wasm32-wasi --toolchain $INSTALLED_NIGHTLY_VERSION
 
     - name: Attempt to load cached GN Third-Party Tools
       uses: actions/cache@v3
@@ -424,6 +493,13 @@ jobs:
     needs: [check]
     steps:
     - uses: actions/checkout@v2
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
     - name: Install cargo-all-features
@@ -465,12 +541,19 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     - name: Load nightly Rust toolchain for WASM.
       run: |
-        rustup install nightly-2022-04-05
-        rustup target add wasm32-unknown-unknown --toolchain nightly-2022-04-05
-        rustup target add wasm32-unknown-emscripten --toolchain nightly-2022-04-05
-        rustup component add rust-src --toolchain nightly-2022-04-05
+        rustup install $INSTALLED_NIGHTLY_VERSION
+        rustup target add wasm32-unknown-unknown --toolchain $INSTALLED_NIGHTLY_VERSION
+        rustup target add wasm32-unknown-emscripten --toolchain $INSTALLED_NIGHTLY_VERSION
+        rustup component add rust-src --toolchain $INSTALLED_NIGHTLY_VERSION
 
     - name: Get cargo-make version
       id: cargo-make-version
@@ -514,7 +597,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
 
@@ -555,7 +644,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
 
@@ -610,10 +705,11 @@ jobs:
   # Clippy job (cargo-clippy) - completes and puts warnings inline in PR
   clippy:
     runs-on: ubuntu-latest
-
+    # We don't expect to keep being clippy-clean on nightly Rust
+    if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
     steps:
-    - uses: actions/checkout@v2
 
+    - uses: actions/checkout@v2
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
 
@@ -631,6 +727,7 @@ jobs:
   # Benchmarking & dashboards job
 
   benchmark:
+    # We don't expect to keep being clippy-clean on nightly Rust
     strategy:
       # max-parallel: 1
       fail-fast: false
@@ -655,6 +752,13 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
 
     - name: Load the default Rust toolchain via the rust-toolchain file.
       run: rustup show
@@ -774,17 +878,23 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
-
+    - name: Potentially override rust version with nightly
+      # pull_request is a fake for me to be able to test this for now
+      if: "github.event_name == 'schedule' || github.event_name == 'pull_request' || (github.event_name == 'workflow_dispatch' && inputs.nightly)"
+      run: |
+        rustup override set nightly
+        echo "ICU4X_NIGHTLY_TOOLCHAIN=nightly" >> $GITHUB_ENV
+        echo "INSTALLED_NIGHTLY_VERSION=nightly" >> $GITHUB_ENV
     # Nightly is only needed for the `--profile bench` line. Once that is stabilized,
     # then this line is no longer needed.
     - uses: actions-rs/toolchain@v1
       with:
-        toolchain: nightly-2022-04-05
+        toolchain: ${{ env.INSTALLED_NIGHTLY_VERSION }}
         override: true
 
     - name: Run the example with dhat-rs to collect memory information
       run: |
-        cargo run --package icu_benchmark_memory -- --os ${{ matrix.os }} ${{ matrix.examples }} --toolchain nightly-2022-04-05
+        cargo run --package icu_benchmark_memory -- --os ${{ matrix.os }} ${{ matrix.examples }} --toolchain $INSTALLED_NIGHTLY_VERSION
 
     # Benchmarking & dashboards job > (unmerged PR only) Convert benchmark output into
     # dashboard HTML in a commit of a branch of the local repo.
@@ -881,8 +991,8 @@ jobs:
     - name: Install prerequisites for wasm build
       run: |
         rustup toolchain list
-        rustup toolchain install nightly-2022-04-05
-        rustup component add --toolchain nightly-2022-04-05 rust-src
+        rustup toolchain install $INSTALLED_NIGHTLY_VERSION
+        rustup component add --toolchain $INSTALLED_NIGHTLY_VERSION rust-src
 
     - name: Install Node.js v16.18.0
       uses: actions/setup-node@v3