Climate Intelligence & Live Weather
Global climate trends, ENSO monitoring, Arctic & Atlantic oscillations, regional impacts, live radar, and snowpack tracking.
Global climate indicators: temperature, greenhouse gases, sea level, and ice. Dashed lines show statistical projections to 2050.
Dashed projection lines are statistical extrapolations of historical trends (polynomial or linear curve fits), not physics-based climate model outputs. Actual outcomes depend on future emission pathways.
ENSO & natural oscillations: Regional precipitation and drought projections use ENSO-aware decomposition — the secular climate trend is separated from the El Niño–Southern Oscillation signal (2–7 year cycles).
For scenario-based projections, see IPCC AR6 WG1 (2021).
US regional precipitation, snowfall, drought, and seasonal temperature changes. Use the dropdowns to toggle between historical and projected views. ENSO filters show how El Niño and La Niña years shift regional patterns.
Dashed projection lines are statistical extrapolations of historical trends, not physics-based climate model outputs.
For scenario-based projections, see IPCC AR6 WG1 (2021).
Estimated climate-health risk indicators. These are conceptual models derived from climate data — not measured health outcomes. For observed health data, see CDC Climate and Health (cdc.gov/climateandhealth).
El Niño–Southern Oscillation monitoring: ONI timeline, Niño region SSTs, phase frequency analysis, SOI correlation, MEI heatmap, teleconnection impacts, and ENSO prediction engine.
The Oceanic Niño Index (ONI) is NOAA CPC's primary indicator for monitoring El Niño and La Niña. It tracks the 3-month running mean of SST anomalies in the Niño 3.4 region (5°N–5°S, 170°W–120°W).
Thresholds: El Niño = ONI ≥ +0.5°C for 5+ consecutive seasons | La Niña = ONI ≤ −0.5°C for 5+ consecutive seasons
Statistical ensemble combining persistence, Ridge regression, and analog methods. Validated on 2020–2026 out-of-sample.
The Oceanic Niño Index (ONI) is the 3-month running mean of SST anomalies in the Niño 3.4 region. NOAA declares El Niño when ONI reaches +0.5°C for 5 consecutive seasons, and La Niña when it drops to −0.5°C.
Probability-weighted expected precipitation anomaly from the ENSO prediction engine. Skillful out to ~6 months; marginal 7–9mo; low skill beyond 10mo.
How the current ENSO state affects seasonal conditions: snowpack, wildfire risk, and temperature patterns.
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Data Sources: NOAA CPC (ONI), NOAA PSL (Niño Indices, SOI, MEI v2), IRI Columbia (ENSO forecasts) | NOAA CAG (Seasonal Temps) | NIFC (Wildfire) | NOAA HURDAT2 (Hurricanes)
Climate teleconnections: how major oscillation patterns across the Arctic, Atlantic, and Pacific interact to drive global weather.
Browse any month from 1950–present to see how each oscillation was behaving.
Pearson correlation between monthly index values over the full overlapping record.
How Pacific ENSO variability couples with Arctic and Atlantic oscillations.
Average index values during El Nino, Neutral, and La Nina months.
Correlation between ENSO (Nino 3.4) this month and each index N months later.
Correlation between December AO/NAO and the following winter's regional temperatures. December is the critical window when the winter pattern locks in.
Rigorous interaction analysis with FDR multiple-testing correction, bootstrap 95% confidence intervals, Cohen's d effect sizes, and train/test temporal validation (pre-1990 / post-1990).
DJF temperature anomaly (°F) by combined ENSO × AO × NAO state across nine US climate regions, 1950–present. Cells with n<5 winters are flagged as low-confidence.
December → January → February AO evolution within compound winters, with bootstrap 95% CIs.
December NAO → winter temperature correlation, separately for active vs. neutral ENSO years.
Measures the pressure difference between the Arctic and mid-latitudes. Positive AO = strong polar vortex. Negative AO = weak vortex, allowing Arctic air to plunge south.
Pressure seesaw between the Icelandic Low and Azores High. Controls European and East Coast winter weather.
Multi-decade swings in North Atlantic SSTs (60–80 year cycle). Modulates hurricane activity and long-term rainfall.
ENSO can influence NAO/AO with a 2–4 month lag. AMO modulates the background state on which ENSO and NAO operate.
Data Sources: NOAA PSL (AO, NAO, AMO indices) | NOAA CPC (ONI) | NOAA PSL (SOI, MEI v2)
A primer on the chemistry and physics of Earth's atmosphere through its interactions with photons. Why sunlight drives nearly every interesting reaction up there, why certain molecules dominate absorption, and where atmospheric CO₂ comes from.
The single most important rule of atmospheric photochemistry: a photon breaks a bond only when its energy exceeds the bond’s dissociation energy. Photon energy scales as E = hc / λ, so shorter wavelengths carry more punch.
Sun (~5780 K) peaks at 0.5 μm — the middle of visible light. Earth (~288 K) peaks at 10 μm — deep in the thermal infrared. Wien’s law (λmax = 2898/T) sets the peak positions; Stefan–Boltzmann (P ∝ T&sup4;) sets the absolute powers.
The same two blackbody curves with the major atmospheric absorption bands superimposed. The vertical bars show which wavelengths each molecule absorbs — the spectral fingerprint of each greenhouse gas.
N₂ (78%) and O₂ (21%) make up 99% of the atmosphere but contribute almost nothing to the greenhouse effect. The selection rule: a vibrational mode is IR-active only if it changes the molecule’s dipole moment. Homonuclear diatomics (N≡N, O=O) have no dipole, no dipole change — IR-invisible.
Homonuclear: no dipole, no IR absorption. Only breaks under extreme UV (<127 nm) in the thermosphere. Its triple bond is one of the strongest in chemistry — this is why nitrogen fixation is so biologically expensive.
Also homonuclear, so IR-invisible. But its electronic structure has accessible excited states: Schumann–Runge bands strip out all UV-C below 242 nm before it can reach the lower atmosphere.
Linear triatomic. Its bending mode at 15 μm sits dead-center on Earth’s thermal emission peak. The symmetric stretch is IR-inactive (symmetry); the asymmetric stretch at 4.3 μm is strong but sits where there’s less Earth emission.
Bent (~104.5°) and permanently polar. All three vibrational modes are IR-active, plus a pure rotational spectrum in the far-IR. Bands are everywhere across the IR — the strongest greenhouse gas by total radiative contribution.
Each bar is the longest wavelength capable of breaking that bond. Color codes which atmospheric layer that wavelength is still abundant in — once a layer absorbs a photon, lower layers don’t see it.
Sydney Chapman, 1930. The most famous piece of atmospheric photochemistry — a self-sustaining cycle that converts UV-C into heat and explains why the ozone layer sits at 25–30 km altitude.
1. O₂ + hν (λ < 242 nm) → 2 O
2. O + O₂ + M → O₃ + M (M = third body, usually N₂)
3. O₃ + hν (λ < 320 nm) → O₂ + O
4. O₃ + O → 2 O₂
The three-body collision in step 2 requires both UV photons (high altitude) and dense enough air for collisions (low altitude). That trade-off pins the ozone peak to 25–30 km. UV absorption in steps 1+3 also heats the stratosphere from the top — that’s why temperature inverts there, killing convection and making the stratosphere the smooth, stable layer airliners cruise in.
Pure Chapman chemistry predicts more ozone than we observe. The real stratosphere has catalytic cycles that destroy O₃ without being consumed themselves. A single Cl atom can take out tens of thousands of ozone molecules.
1. X + O₃ → XO + O₂
2. XO + O → X + O₂
Net: O₃ + O → 2 O₂ (X regenerated — catalytic)
The four major catalytic families are NOx, HOx, ClOx, and BrOx. The Antarctic ozone hole adds a wrinkle: heterogeneous chemistry on polar stratospheric clouds releases active Cl from reservoir species (HCl, ClONO₂), and a ClO+ClO dimer cycle takes over in the lower stratosphere where atomic O is scarce. The Montreal Protocol (1987) is the rare environmental success story — stratospheric chlorine peaked around 2000 and is slowly declining.
Down where we live, the dominant photon-driven species is the hydroxyl radical, OH. Extremely reactive (lifetime ~1 second), it removes most pollutants from the atmosphere — methane, CO, volatile organics. Its production is a chain reaction starting with ozone photolysis.
1. O₃ + hν (λ < 320 nm) → O(¹D) + O₂
2. O(¹D) + H₂O → 2 OH
3. OH + CH₄ → CH₃ + H₂O (methane removal — the main CH₄ sink)
The atmospheric lifetime of methane (~9 years) is set almost entirely by reaction with OH. If you emit a lot of CO, it competes for OH and methane lifetime gets longer — an active debate in atmospheric science is whether global OH is being depleted and what that means for the methane budget.
The chemistry behind “ground-level ozone” warnings on hot summer days. The starring photon-driven reaction is NO₂ photolysis — the only significant source of ozone in the troposphere.
1. NO₂ + hν (λ < 410 nm) → NO + O
2. O + O₂ + M → O₃ + M
3. NO + O₃ → NO₂ + O₂ (VOC-fueled cycles tip the balance toward O₃ buildup)
The cruel irony: stratospheric ozone is a UV shield we want lots of; tropospheric ozone is a respiratory irritant and powerful greenhouse gas we want much less. Same molecule, totally different role depending on altitude. Wildfire smoke (VOCs) + traffic NOx + high-altitude UV makes Front Range summer ozone among the worst in the country.
Pre-industrial CO₂ was ~280 ppm. We’ve added roughly 150 ppm — a ~53% increase — almost all of it in the last 150 years, with the rate accelerating. This is the highest atmospheric CO₂ concentration in over 2 million years.
Total global anthropogenic CO₂ emissions in 2025 are ~41 Gt. About 90% comes from fossil fuels and cement, 10% from land use change (mostly deforestation).
Annual emissions have grown ~20-fold since 1900. About half of all CO₂ humans have ever emitted has been released since around 1990. Visible dips are real economic events — Great Depression, oil shock, 2008 crisis, COVID.
At the center of the 15 μm CO₂ band, every IR photon is already absorbed within hundreds of meters — the band is saturated. Adding CO₂ works only at the band edges, which is why forcing scales logarithmically with concentration: ΔF ≈ 5.35 × ln(C / C₀).
Visible photons excite vibrations; UV breaks bonds; EUV ionizes. Below ~242 nm you can break O₂; below ~127 nm you can break N₂.
A molecule absorbs only at quantum-allowed transitions. N₂/O₂ are transparent in the visible because they have no allowed transitions there.
When the active species regenerates each cycle, tiny amounts cause enormous damage. CFCs and OH both follow this template.
Three-body reactions (O + O₂ + M → O₃) need dense air. Altitude shifts which chemistry runs even when the same photons are available.
A molecule must live long enough to arrive where it acts. CFCs (50–100 yr) survive the troposphere intact and deliver chlorine aloft; OH (~1 s) cleans the troposphere precisely because it disappears fast. CO₂'s multi-century lifetime is why emissions today commit centuries of forcing; methane's ~12-year lifetime is why CH₄ cuts pay off quickly.
ΔF = 5.35 · ln(C/C₀) gives ~3.7 W/m² per doubling of CO₂ regardless of starting concentration. The climate system converts that to ~1 K bare Planck response, amplified to ~3 K by water-vapor, ice-albedo, and cloud feedbacks. Yet warming scales linearly with cumulative emissions — ~0.45 K per 1000 GtCO₂ (TCRE). The log dependence on ppm and the linear dependence on cumulative carbon are the same fact viewed from opposite ends.
Reference data: NOAA GML Mauna Loa (CO₂); Global Carbon Budget 2025 (emissions); IPCC AR6 WG1 (radiative forcing); HITRAN (absorption lines). Bond energies and reaction rates from standard atmospheric chemistry references (Seinfeld & Pandis, Brasseur & Solomon).
Live precipitation radar, snow cover imagery, and SNOTEL station data. Data updates automatically from public APIs.
Data: RainViewer (Precipitation Radar) | Iowa State Mesonet (NEXRAD) | NASA GIBS (VIIRS Snow Cover) | NOAA NOHRSC (SWE) | USDA NRCS SNOTEL (Snowpack)