What temperature are dry ice packs under real shipping conditions? At standard pressure, dry ice sits at −78.5 °C (−109.3 °F). In a shipper, internal air typically holds between about −70 °C and −20 °C depending on insulation, venting, and pack placement. You’ll see why this range matters, how much dry ice to use, and how to stay compliant in 2025.
Exact numbers: what temperature are dry ice packs at the surface, in the box air, and at the product core
Sizing made simple: quick math for sublimation rates and a dry ice quantity estimator
Safer pack-outs: venting, labels (UN1845), and spacing to prevent freeze damage
Smart choices: when dry ice beats gel/PCM—and when it doesn’t
Trends for 2025: vent membranes, edge-aware loggers, CO₂ recovery, and digital DG workflows
What temperature are dry ice packs under real shipping conditions?
Short answer: Dry ice is −78.5 °C at the source; box air stabilizes warmer (≈ −70 °C to −20 °C). Product core lags the air and stays below its spec if you size mass and insulation correctly. This is why what temperature are dry ice packs is a system question, not just a single number.
Why it matters: If you must hold ≤−18/−20 °C (ice cream, frozen desserts, some biologics), a −78.5 °C “cold battery” gives large safety headroom. For 2–8 °C, dry ice is too cold—use gel or PCM to avoid accidental freezing.
How much dry ice to start with?
A practical daily estimator is:
Dry ice (lb) = (Transit hours ÷ 24) × Sublimation rate (lb/24 h)
Plan with typical rates by shipper quality and add a 10–30 % buffer for hand-offs and ambient spikes.
| Shipper Type | Insulation Quality | Typical Sublimation (lb/24 h) | What it means for you |
|---|---|---|---|
| EPS foam (≈ 2″ wall) | Excellent | 4–6 | Great for 48–72 h lanes |
| Rigid plastic + liner | Good | 6–8 | Balanced cost/hold |
| Corrugated + liner | Moderate | 8–10 | Add mass or shorten route |
| Pallet foam crate | Premium | 10–20 / pallet | Scale with openings and cube |
Pro tip: It’s often cheaper to improve insulation than to keep adding dry ice. Better walls reduce loss across every touchpoint.
Pack placement patterns that actually work
Top-load only: cold sinks; watch bottom warm-up on longer lanes
Top + bottom: flatter gradients for mixed-density loads
Surround (sides + top): most uniform profile; needs more initial mass
Interstitial (between layers): fast pull-down; add spacers for fragile packs
Real-world snapshot: A dessert brand cut temperature excursions by 38 % after switching from top-only blocks to a surround pellet pattern with the same mass.
What temperature are dry ice packs vs. gel and PCM packs?
Bottom line: Use dry ice for frozen (≤−20 °C). Use gel/PCM for 2–8 °C or CRT.
| Cooling Element | Set-Point / Behavior | Best Use | Watch-outs |
|---|---|---|---|
| Dry ice (CO₂ UN1845) | −78.5 °C sublimes | Deep-frozen lanes | Venting required |
| Gel pack (0 °C) | 0 °C melts | Chilled food | Short hold |
| PCM −21 °C | Phase at −21 °C | Frozen foods | Pre-condition |
| PCM +5 °C | Phase ≈ +5 °C | Vaccines | Avoid freezing |
| PCM +22 °C | Phase ≈ +22 °C | CRT lanes | Needs insulation |
What temperature are dry ice packs at the product interface—and is it safe?
Contact risk: A −78.5 °C surface can freeze sensitive items on contact. Add a spacer (corrugate, foam tray) and distribute packs evenly.
Compliance checklist
Proper name “Carbon dioxide, solid (Dry ice), UN1845”
Net weight of dry ice on package
Vented (never airtight) container
Class 9 hazard label
Helpful decision tools
Check the details before you choose packaging
These quick tools can help you compare route risk, sizing needs, coolant choices, and packaging details before you request a quote.
01Dry ice planningDry Ice Calculator
Estimate dry ice needs for frozen or ultra-cold shipments before packing.
Estimate dry ice02Packaging choicePackaging Selector
Compare insulated packaging options by product, route, and temperature need.
Find packaging03Coolant choiceCoolant & PCM Reference
Compare coolant and PCM options when a route needs added temperature support.
Compare optionsClear shipper / consignee info
| Topic | Essential Practice | What to Avoid | Why it matters |
|---|---|---|---|
| Venting | Use vent gaps | Airtight lids | Prevents pressure buildup |
| Labeling | UN1845 + weight + Class 9 | Missing weights | Faster acceptance |
| Handling | Insulated gloves | Bare-hand contact | Avoids frost injury |
Practical tips
Door cycles: minimize openings
Logger location: near payload core
Lane design: prefer predictable curves, not perfect symmetry
How much dry ice do you need for 24–96 h lanes?
Example: 48 h lane, EPS shipper, ≈ 5 lb / 24 h →
(48 / 24) × 5 = 10 lb + 10–20 % buffer → 11–12 lb total.
Validation beats theory—tune to your kit and lanes.
2025 trends in dry ice temperature control
Fresh in 2025: Smarter vent membranes, edge-aware loggers, CO₂ recapture, and digital DG workflows cut cost and emissions.
Highlights
Microporous vent lids stabilize internal air
Edge-aware loggers catch corner leaks early
Lower-carbon dry ice from CO₂ capture
Digital declarations reduce errors
Market insight: Frozen DTC and biologics growth favors lighter, surround pack-outs with better insulation for cost control.
FAQs
Q1: What temperature are dry ice packs at the start of a trip?
About −78.5 °C at surface/core; internal air warms to −70 °C to −20 °C depending on design.
Q2: Can I use dry ice for 2–8 °C?
No. It’s too cold—use +5 °C PCM or gel packs.
Q3: Pellets or slabs?
Pellets distribute evenly; slabs last longer. Hybrid works best.
Q4: How close can dry ice be to my product?
Avoid direct contact; use a spacer and rely on box air temp.
Q5: How long does dry ice last?
Typically 18–96 h depending on insulation, mass, and ambient.
Summary & recommendations
Key points: What temperature are dry ice packs = −78.5 °C source; box air warmer.
Use dry ice for frozen lanes, PCM/gel for 2–8 °C. Always vent, label, and log.
Next steps:
Define target temp & lane time.
Choose correct coolant.
Estimate mass + 10–30 % buffer.
Use Top+Bottom or Surround layout.
Validate with loggers.
CTA: Ready to validate a −20 °C or −70 °C lane? Book a 10-minute pack-out review with Tempk.
About Tempk
We design validated frozen, refrigerated, and CRT pack-outs with proven insulation and accessories that hit −20 °C and −70 °C profiles reliably. Every design is backed by pilot data and SOPs that teams can follow easily.
