diff --git a/Cargo.lock b/Cargo.lock
index 5856799..b94a685 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -17,6 +17,12 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
 
+[[package]]
+name = "adler32"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aae1277d39aeec15cb388266ecc24b11c80469deae6067e17a1a7aa9e5c1f234"
+
 [[package]]
 name = "ansi_term"
 version = "0.12.1"
@@ -103,7 +109,7 @@ dependencies = [
  "cc",
  "cfg-if 1.0.0",
  "libc",
- "miniz_oxide",
+ "miniz_oxide 0.4.4",
  "object",
  "rustc-demangle",
 ]
@@ -126,6 +132,12 @@ version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "383d29d513d8764dcdc42ea295d979eb99c3c9f00607b3692cf68a431f7dca72"
 
+[[package]]
+name = "bit_field"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dcb6dd1c2376d2e096796e234a70e17e94cc2d5d54ff8ce42b28cef1d0d359a4"
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -138,6 +150,18 @@ version = "3.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a4a45a46ab1f2412e53d3a0ade76ffad2025804294569aae387231a0cd6e0899"
 
+[[package]]
+name = "bytemuck"
+version = "1.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "439989e6b8c38d1b6570a384ef1e49c8848128f5a97f3914baef02920842712f"
+
+[[package]]
+name = "byteorder"
+version = "1.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "14c189c53d098945499cdfa7ecc63567cf3886b3332b312a5b4585d8d3a6a610"
+
 [[package]]
 name = "bytes"
 version = "0.5.6"
@@ -209,6 +233,12 @@ dependencies = [
  "tracing-error",
 ]
 
+[[package]]
+name = "color_quant"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d7b894f5411737b7867f4827955924d7c254fc9f4d91a6aad6b097804b1018b"
+
 [[package]]
 name = "const_fn"
 version = "0.4.9"
@@ -242,6 +272,68 @@ version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5827cebf4670468b8772dd191856768aedcb1b0278a04f989f7766351917b9dc"
 
+[[package]]
+name = "crc32fast"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b540bd8bc810d3885c6ea91e2018302f68baba2129ab3e88f32389ee9370880d"
+dependencies = [
+ "cfg-if 1.0.0",
+]
+
+[[package]]
+name = "crossbeam-channel"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e54ea8bc3fb1ee042f5aace6e3c6e025d3874866da222930f70ce62aceba0bfa"
+dependencies = [
+ "cfg-if 1.0.0",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6455c0ca19f0d2fbf751b908d5c55c1f5cbc65e03c4225427254b46890bdde1e"
+dependencies = [
+ "cfg-if 1.0.0",
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c00d6d2ea26e8b151d99093005cb442fb9a37aeaca582a03ec70946f49ab5ed9"
+dependencies = [
+ "cfg-if 1.0.0",
+ "crossbeam-utils",
+ "lazy_static",
+ "memoffset",
+ "scopeguard",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5e5bed1f1c269533fa816a0a5492b3545209a205ca1a54842be180eb63a16a6"
+dependencies = [
+ "cfg-if 1.0.0",
+ "lazy_static",
+]
+
+[[package]]
+name = "deflate"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c86f7e25f518f4b81808a2cf1c50996a61f5c2eb394b2393bd87f2a4780a432f"
+dependencies = [
+ "adler32",
+]
+
 [[package]]
 name = "devise"
 version = "0.3.1"
@@ -296,6 +388,22 @@ dependencies = [
  "cfg-if 1.0.0",
 ]
 
+[[package]]
+name = "exr"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d4badb9489a465cb2c555af1f00f0bfd8cecd6fc12ac11da9d5b40c5dd5f0200"
+dependencies = [
+ "bit_field",
+ "deflate",
+ "flume",
+ "half",
+ "inflate",
+ "lebe",
+ "smallvec",
+ "threadpool",
+]
+
 [[package]]
 name = "eyre"
 version = "0.6.6"
@@ -329,6 +437,31 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "flate2"
+version = "1.0.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e6988e897c1c9c485f43b47a529cef42fde0547f9d8d41a7062518f1d8fc53f"
+dependencies = [
+ "cfg-if 1.0.0",
+ "crc32fast",
+ "libc",
+ "miniz_oxide 0.4.4",
+]
+
+[[package]]
+name = "flume"
+version = "0.10.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d04dafd11240188e146b6f6476a898004cace3be31d4ec5e08e216bf4947ac0"
+dependencies = [
+ "futures-core",
+ "futures-sink",
+ "nanorand",
+ "pin-project",
+ "spin",
+]
+
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -498,7 +631,7 @@ dependencies = [
  "geo-types",
  "hyper 0.13.10",
  "num-traits",
- "reqwest",
+ "reqwest 0.10.10",
  "serde",
  "serde_json",
  "thiserror",
@@ -511,8 +644,20 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "418d37c8b1d42553c93648be529cb70f920d3baf8ef469b74b9638df426e0b4c"
 dependencies = [
  "cfg-if 1.0.0",
+ "js-sys",
  "libc",
  "wasi",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "gif"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c3a7187e78088aead22ceedeee99779455b23fc231fe13ec443f99bb71694e5b"
+dependencies = [
+ "color_quant",
+ "weezl",
 ]
 
 [[package]]
@@ -566,6 +711,12 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "half"
+version = "1.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eabb4a44450da02c90444cf74558da904edde8fb4e9035a9a6a4e15445af0bd7"
+
 [[package]]
 name = "hashbrown"
 version = "0.11.2"
@@ -692,6 +843,19 @@ dependencies = [
  "tokio-tls",
 ]
 
+[[package]]
+name = "hyper-tls"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6183ddfa99b85da61a140bea0efc93fdf56ceaa041b37d553518030827f9905"
+dependencies = [
+ "bytes 1.1.0",
+ "hyper 0.14.17",
+ "native-tls",
+ "tokio 1.16.1",
+ "tokio-native-tls",
+]
+
 [[package]]
 name = "idna"
 version = "0.2.3"
@@ -703,6 +867,26 @@ dependencies = [
  "unicode-normalization",
 ]
 
+[[package]]
+name = "image"
+version = "0.24.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e94ac3d41f882c624a82d7945952032388488681f45f9d4077999a6c85688d61"
+dependencies = [
+ "bytemuck",
+ "byteorder",
+ "color_quant",
+ "exr",
+ "gif",
+ "jpeg-decoder 0.2.1",
+ "num-iter",
+ "num-rational",
+ "num-traits",
+ "png",
+ "scoped_threadpool",
+ "tiff",
+]
+
 [[package]]
 name = "indenter"
 version = "0.3.3"
@@ -720,6 +904,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "inflate"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1cdb29978cc5797bd8dcc8e5bf7de604891df2a8dc576973d71a281e916db2ff"
+dependencies = [
+ "adler32",
+]
+
 [[package]]
 name = "inlinable_string"
 version = "0.1.15"
@@ -762,6 +955,21 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1aab8fc367588b89dcee83ab0fd66b72b50b72fa1904d7095045ace2b0c81c35"
 
+[[package]]
+name = "jpeg-decoder"
+version = "0.1.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "229d53d58899083193af11e15917b5640cd40b29ff475a1fe4ef725deb02d0f2"
+
+[[package]]
+name = "jpeg-decoder"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fbcf0244f6597be39ab8d9203f574cafb529ae8c698afa2182f7b3c3205a4a9c"
+dependencies = [
+ "rayon",
+]
+
 [[package]]
 name = "js-sys"
 version = "0.3.56"
@@ -787,6 +995,12 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
+[[package]]
+name = "lebe"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7efd1d698db0759e6ef11a7cd44407407399a910c774dd804c64c032da7826ff"
+
 [[package]]
 name = "libc"
 version = "0.2.117"
@@ -847,6 +1061,15 @@ version = "2.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "308cc39be01b73d0d18f82a0e7b2a3df85245f84af96fdddc5d202d27e47b86a"
 
+[[package]]
+name = "memoffset"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5aa361d4faea93603064a027415f07bd8e1d5c88c9fbf68bf56a285428fd79ce"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "mime"
 version = "0.3.16"
@@ -873,6 +1096,15 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "miniz_oxide"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2b29bd4bc3f33391105ebee3589c19197c4271e3e5a9ec9bfe8127eeff8f082"
+dependencies = [
+ "adler",
+]
+
 [[package]]
 name = "mio"
 version = "0.6.23"
@@ -946,6 +1178,15 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "nanorand"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "729eb334247daa1803e0a094d0a5c55711b85571179f5ec6e53eccfdf7008958"
+dependencies = [
+ "getrandom",
+]
+
 [[package]]
 name = "native-tls"
 version = "0.2.8"
@@ -994,6 +1235,28 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "num-iter"
+version = "0.1.42"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b2021c8337a54d21aca0d59a92577a029af9431cb59b909b03252b9c164fad59"
+dependencies = [
+ "autocfg",
+ "num-integer",
+ "num-traits",
+]
+
+[[package]]
+name = "num-rational"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d41702bd167c2df5520b384281bc111a4b5efcf7fbc4c9c222c815b07e0a6a6a"
+dependencies = [
+ "autocfg",
+ "num-integer",
+ "num-traits",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.2.14"
@@ -1165,6 +1428,18 @@ version = "0.3.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "58893f751c9b0412871a09abd62ecd2a00298c6c83befa223ef98c52aef40cbe"
 
+[[package]]
+name = "png"
+version = "0.17.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e8f1882177b17c98ec33a51f5910ecbf4db92ca0def706781a1f8d0c661f393"
+dependencies = [
+ "bitflags",
+ "crc32fast",
+ "deflate",
+ "miniz_oxide 0.5.1",
+]
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.16"
@@ -1248,6 +1523,31 @@ dependencies = [
  "rand_core",
 ]
 
+[[package]]
+name = "rayon"
+version = "1.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c06aca804d41dbc8ba42dfd964f0d01334eceb64314b9ecf7c5fad5188a06d90"
+dependencies = [
+ "autocfg",
+ "crossbeam-deque",
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d78120e2c850279833f1dd3582f730c4ab53ed95aeaaaa862a2a5c71b1656d8e"
+dependencies = [
+ "crossbeam-channel",
+ "crossbeam-deque",
+ "crossbeam-utils",
+ "lazy_static",
+ "num_cpus",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.2.10"
@@ -1324,7 +1624,7 @@ dependencies = [
  "http",
  "http-body 0.3.1",
  "hyper 0.13.10",
- "hyper-tls",
+ "hyper-tls 0.4.3",
  "ipnet",
  "js-sys",
  "lazy_static",
@@ -1346,6 +1646,42 @@ dependencies = [
  "winreg",
 ]
 
+[[package]]
+name = "reqwest"
+version = "0.11.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87f242f1488a539a79bac6dbe7c8609ae43b7914b7736210f239a37cccb32525"
+dependencies = [
+ "base64",
+ "bytes 1.1.0",
+ "encoding_rs",
+ "futures-core",
+ "futures-util",
+ "h2 0.3.11",
+ "http",
+ "http-body 0.4.4",
+ "hyper 0.14.17",
+ "hyper-tls 0.5.0",
+ "ipnet",
+ "js-sys",
+ "lazy_static",
+ "log",
+ "mime",
+ "native-tls",
+ "percent-encoding",
+ "pin-project-lite 0.2.8",
+ "serde",
+ "serde_json",
+ "serde_urlencoded",
+ "tokio 1.16.1",
+ "tokio-native-tls",
+ "url",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+ "winreg",
+]
+
 [[package]]
 name = "rocket"
 version = "0.5.0-rc.1"
@@ -1472,6 +1808,12 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ea6a9290e3c9cf0f18145ef7ffa62d68ee0bf5fcd651017e586dc7fd5da448c2"
 
+[[package]]
+name = "scoped_threadpool"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d51f5df5af43ab3f1360b429fa5e0152ac5ce8c0bd6485cae490332e96846a8"
+
 [[package]]
 name = "scopeguard"
 version = "1.1.0"
@@ -1599,7 +1941,9 @@ dependencies = [
  "chrono",
  "color-eyre",
  "geocoding",
+ "image",
  "once_cell",
+ "reqwest 0.11.9",
  "rocket",
 ]
 
@@ -1641,6 +1985,9 @@ name = "spin"
 version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "511254be0c5bcf062b019a6c89c01a664aa359ded62f78aa72c6fc137c0590e5"
+dependencies = [
+ "lock_api",
+]
 
 [[package]]
 name = "stable-pattern"
@@ -1772,6 +2119,26 @@ dependencies = [
  "once_cell",
 ]
 
+[[package]]
+name = "threadpool"
+version = "1.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d050e60b33d41c19108b32cea32164033a9013fe3b46cbd4457559bfbf77afaa"
+dependencies = [
+ "num_cpus",
+]
+
+[[package]]
+name = "tiff"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0247608e998cb6ce39dfc8f4a16c50361ce71e5b52e6d24ea1227ea8ea8ee0b2"
+dependencies = [
+ "flate2",
+ "jpeg-decoder 0.1.22",
+ "weezl",
+]
+
 [[package]]
 name = "time"
 version = "0.1.44"
@@ -1883,6 +2250,16 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "tokio-native-tls"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f7d995660bd2b7f8c1568414c1126076c13fbb725c40112dc0120b78eb9b717b"
+dependencies = [
+ "native-tls",
+ "tokio 1.16.1",
+]
+
 [[package]]
 name = "tokio-stream"
 version = "0.1.8"
@@ -2220,6 +2597,12 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "weezl"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d8b77fdfd5a253be4ab714e4ffa3c49caf146b4de743e97510c0656cf90f1e8e"
+
 [[package]]
 name = "winapi"
 version = "0.2.8"
diff --git a/Cargo.toml b/Cargo.toml
index ccb6e2a..ffb7b2e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,5 +7,7 @@ edition = "2021"
 chrono = "0.4.19"
 color-eyre = "0.5.6"
 geocoding = "0.3.1"
+image = "0.24.0"
 once_cell = "1.9.0"
+reqwest = "0.11.9"
 rocket = { version = "0.5.0-rc.1", features = ["json"] }
diff --git a/src/main.rs b/src/main.rs
index 0c9696d..c4b3972 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -24,7 +24,8 @@ use self::maps::Maps;
 
 mod maps;
 
-static MAPS: Lazy<Mutex<Maps>> = Lazy::new(|| Mutex::new(Maps::default()));
+/// Global maps cache refreshed by a separate task.
+static MAPS: Lazy<Mutex<Maps>> = Lazy::new(|| Mutex::new(Maps::new()));
 
 /// The current for a specific location.
 ///
@@ -198,7 +199,7 @@ async fn main() -> Result<()> {
         .await?;
     let shutdown = rocket.shutdown();
 
-    let maps_updater = tokio::spawn(Maps::run());
+    let maps_updater = tokio::spawn(maps::run());
 
     select! {
         result = rocket.launch() => {
diff --git a/src/maps.rs b/src/maps.rs
index aa639d0..e53ba46 100644
--- a/src/maps.rs
+++ b/src/maps.rs
@@ -1,21 +1,145 @@
-//! Maps handling.
+//! Maps retrieval and caching.
+//!
+//! This module provides a task that keeps maps up-to-date using a maps-specific refresh interval.
+//! It stores all the maps as [`DynamicImage`]s in memory.
 
-use rocket::tokio::time::{sleep, Duration};
+use chrono::DurationRound;
+use image::DynamicImage;
+use rocket::tokio::time::{sleep, Duration, Instant};
 
 use crate::MAPS;
 
 /// The interval between map refreshes (in seconds).
-const SLEEP_INTERVAL: u64 = 60;
+const SLEEP_INTERVAL: Duration = Duration::from_secs(60);
 
-#[derive(Debug, Default)]
-pub(crate) struct Maps;
+/// The base URL for retrieving the precipitation map.
+const PRECIPITATION_BASE_URL: &str =
+    "https://cluster.api.meteoplaza.com/v3/nowcast/tiles/radarnl-forecast";
+
+/// The interval for retrieving precipitation maps.
+const PRECIPITATION_INTERVAL: Duration = Duration::from_secs(300);
+
+/// The base URL for retrieving the pollen maps.
+const POLLEN_BASE_URL: &str =
+    "https://image.buienradar.nl/2.0/image/sprite/WeatherMapPollenRadarHourlyNL\
+        ?height=988&width=820&extension=png&renderBackground=False&renderBranding=False\
+        &renderText=False&history=0&forecast=24&skip=0&timestamp=";
+
+/// The interval for retrieving pollen maps.
+const POLLEN_INTERVAL: Duration = Duration::from_secs(600);
+
+/// The base URL for retrieving the UV index maps.
+const UVI_BASE_URL: &str = "https://image.buienradar.nl/2.0/image/sprite/WeatherMapUVIndexNL\
+        ?extension=png&width=820&height=988&renderText=False&renderBranding=False\
+        &renderBackground=False&history=0&forecast=5&skip=0&timestamp=";
+
+/// The interval for retrieving UV index maps.
+const UVI_INTERVAL: Duration = Duration::from_secs(3600);
+
+/// Runs a loop that keeps refreshing the maps when necessary.
+pub(crate) async fn run() -> ! {
+    loop {
+        let mut maps = MAPS.lock().await;
+
+        println!("🕔 Refreshing the maps (if necessary)...");
+        maps.refresh_precipitation().await;
+        maps.refresh_pollen().await;
+        maps.refresh_uvi().await;
+
+        sleep(SLEEP_INTERVAL).await;
+    }
+}
+
+/// Container type for all in-memory cached maps.
+#[derive(Debug)]
+pub(crate) struct Maps {
+    /// The pollen maps (from Buienradar).
+    pub(crate) pollen: Option<DynamicImage>,
+
+    /// The timestamp the pollen maps were last refreshed.
+    pollen_stamp: Instant,
+
+    /// The precipitation maps (from Weerplaza).
+    // TODO: Make one large image instead of using an array? This is already the case for the
+    //   other maps.
+    pub(crate) precipitation: [Option<DynamicImage>; 24],
+
+    /// The timestamp the precipitation maps were last refreshed.
+    precipitation_stamp: Instant,
+
+    /// The UV index maps (from Buienradar).
+    pub(crate) uvi: Option<DynamicImage>,
+
+    /// The timestamp the UV index maps were last refreshed.
+    uvi_stamp: Instant,
+}
 
 impl Maps {
-    pub(crate) async fn run() -> ! {
-        loop {
-            let _maps = MAPS.lock().await;
+    pub(crate) fn new() -> Self {
+        let now = Instant::now();
+        // Because `Option<DynamicImage>` does not implement `Copy`
+        let precipitation = [(); 24].map(|_| None);
 
-            sleep(Duration::from_secs(SLEEP_INTERVAL)).await;
+        Self {
+            pollen: None,
+            pollen_stamp: now,
+            precipitation,
+            precipitation_stamp: now,
+            uvi: None,
+            uvi_stamp: now,
+        }
+    }
+
+    async fn refresh_precipitation(&mut self) {
+        if self.precipitation.iter().any(|map| map.is_none())
+            || Instant::now().duration_since(self.precipitation_stamp) > PRECIPITATION_INTERVAL
+        {
+            let just_before = (chrono::Utc::now() - chrono::Duration::minutes(10))
+                // This only fails if timestamps and durations exceed limits!
+                .duration_trunc(chrono::Duration::minutes(5))
+                .unwrap();
+            let timestamp = just_before.format("%Y%m%d%H%M");
+
+            for k in 0..24 {
+                let suffix = format!("{:03}", k * 5);
+                let url = format!("{PRECIPITATION_BASE_URL}/{timestamp}_{suffix}");
+                println!("🔽 Refreshing precipitation maps from: {}", url);
+                self.precipitation[k] = retrieve_image(&url).await;
+            }
+            self.precipitation_stamp = Instant::now();
+        }
+    }
+
+    async fn refresh_pollen(&mut self) {
+        if self.pollen.is_none()
+            || Instant::now().duration_since(self.pollen_stamp) > POLLEN_INTERVAL
+        {
+            let timestamp = chrono::Local::now().format("%y%m%d%H%M");
+            let url = format!("{POLLEN_BASE_URL}{timestamp}");
+
+            println!("🔽 Refreshing pollen maps from: {}", url);
+            self.pollen = retrieve_image(&url).await;
+            self.pollen_stamp = Instant::now();
+        }
+    }
+
+    async fn refresh_uvi(&mut self) {
+        if self.uvi.is_none() || Instant::now().duration_since(self.uvi_stamp) > UVI_INTERVAL {
+            let timestamp = chrono::Local::now().format("%y%m%d%H%M");
+            let url = format!("{UVI_BASE_URL}{timestamp}");
+
+            println!("🔽 Refreshing UV index maps from: {}", url);
+            self.uvi = retrieve_image(&url).await;
+            self.uvi_stamp = Instant::now();
         }
     }
 }
+
+/// Retrieves an image from the provided URL.
+async fn retrieve_image(url: &str) -> Option<DynamicImage> {
+    // TODO: Handle or log errors!
+    let response = reqwest::get(url).await.ok()?;
+    let bytes = response.bytes().await.ok()?;
+
+    image::load_from_memory(&bytes).ok()
+}