Samsara Fuel Spend Index

Diesel prices rose 4.17% week over week to $5.53, a new all-time high that surpasses the June 2022 energy-crisis peak ($5.50). The four-week deceleration trend is broken — this is a reacceleration, not a plateau. Early Week 15 data shows gasoline collapsing 10.4% on crude's 7%+ drop following Iran ceasefire announcements, while diesel holds firm at −0.26%. The divergence is structural.

• Diesel: $5.53 (+4.17% WoW, +67.46% vs Dec 29)

• Gasoline: $4.37 (+2.33% WoW, +48.16% vs Dec 29)

• 3-week diesel change (W11 → W14): +9.89%

• Diesel–gas spread: $1.16 (vs $0.35 baseline)

(Note: Last week's preliminary diesel price of $5.59 settled to $5.53. This week's WoW is calculated from the settled W13 figure of $5.31.)

WHAT CHANGED THIS WEEK

• Diesel reaccelerated to +4.17% WoW, up from +2.53% the prior week — breaking the four-week deceleration trend (calculated from settled $5.31, not the preliminary $5.59)

• Gasoline increased 2.33% WoW, slowing from +2.50% — diesel WoW overtook gasoline again, reversing last week's flip

• 22.3% of the total diesel increase since Dec 29 occurred in the last 3 weeks (since W11)

• The diesel–gas spread widened to $1.16, up from $1.02 in W13. Last week's spread compression has reversed. Early W15 data shows the spread surging to $1.60, as gasoline collapsed (−10.4% WoW) while diesel held (−0.26%). The structural divergence we describe below is already visible in the data.

Interpretation: In isolation, W13 continued the deceleration trend — diesel WoW dropped from +12.8% (W10) → +4.8% (W11) → +2.9% (W12) → +2.5% (W13). W14 broke that trend with a +4.17% WoW reacceleration, setting a new all-time high at $5.53 that surpasses the June 2022 energy-crisis peak ($5.50). The plateau thesis is not confirmed. Meanwhile, early W15 data introduces a new variable: crude dropped 7%+ on Iran ceasefire news, and gasoline followed it down immediately. Diesel did not. This asymmetry will define the next phase of the market.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: Hawaii ($7.16), California ($7.01), Washington ($6.65)

• Lowest diesel states: North Dakota ($4.84), Montana ($4.95), Oklahoma ($4.98)

• National spread: $2.32 between highest and lowest states

Hawaii posted the largest single-week jump (+$0.74), while Michigan (+$0.47) and Ohio (+$0.40) also saw outsized increases — the Midwest is now seeing the repricing wave that started on the coasts. Only 2 states saw WoW decreases (Utah, Idaho), both modest. All 50 states are now positive YoY, with Oregon leading at +86.3% and Arizona at +$2.82 in absolute terms.

California note: Phillips 66 Wilmington (LA) ceased refining in late 2025, and Valero Benicia (Bay Area) is idling as of April 2026 — a combined 284,000 bbl/day of lost capacity. California's premium reflects real supply constraints, not just regulatory costs.

WHAT THIS MEANS

This week told two stories — and the second one matters more.

The W14 data confirmed what the preliminary numbers hinted at last week: the deceleration was a pause, not a plateau. Diesel reaccelerated to +4.17% WoW, setting a new all-time high at $5.53 that eclipses the June 2022 energy-crisis peak. 48 of 50 states posted WoW increases. The repricing wave is broadening inland, with Midwest states (MI, OH, IL, IN, MN) posting outsized gains.

But the real story is the forward-looking divergence emerging in W15.

The differences from 2022 are structural:

• The 2022 peak was a sharp supply-shock spike that reversed within weeks

• The current repricing has been a grinding 15-week ascent with no reversal signals — 48 of 50 states still posted WoW increases in W14

• At $5.53, diesel is already 67.5% above Dec 29; the 2022 peak ($5.50) has been surpassed

The diesel–gasoline split is now structural, not cyclical. Crude oil dropped over 7% this past week on ceasefire announcements related to Iran, and gasoline — essentially a spot-price product — followed it down within days. Early W15 data shows gasoline collapsing 10.4% WoW to $3.92. Diesel barely moved: −0.26% to $5.52. The spread widened from $1.16 to $1.60 in a single week.

Three structural drivers explain why diesel has a floor that gasoline doesn't:

• U.S. diesel inventories have been running below the five-year average. EIA projects distillate inventories ending 2025–2026 at multi-year lows — potentially the lowest since 2000.

• Refinery capacity losses — Phillips 66 Wilmington, Valero Benicia, and LyondellBasell Houston represent ~284,000+ bbl/day of permanent or semi-permanent closures that tighten the diesel market structurally.

• Diesel has inelastic demand from freight, agriculture, and industry that doesn't flex like consumer gasoline demand. Refiners have been prioritizing diesel yield because margins are better, keeping supply tight even when crude eases.

The strategic question has shifted again: this is no longer about whether prices plateau at $5.53 — it's about whether the Iran ceasefire represents a sustained crude correction or a temporary dip that diesel's structural tightness will absorb. If crude stays lower, we may see the most divergent diesel–gasoline spread environment since this repricing cycle began. The W15 data, once settled, will be the first real test of whether geopolitical relief can offset structural supply constraints.

METHODOLOGY Aggregated weekly average fuel prices paid by customers; baseline = week of Dec 29, 2025. W14 preliminary diesel of $5.59 settled to $5.53; all calculations use settled figures. W15 data referenced in forward-looking commentary is preliminary and subject to settlement revisions.

Diesel prices rose 2.51% week over week to $5.31, extending a 62.50% increase since year start. The four-week deceleration trend appeared intact; however, early Week 14 data already show prices surging to $5.59, a new all-time high that surpasses the June 2022 energy-crisis peak. We’ll continue to monitor throughout the week. 

• Diesel: $5.31 (+2.51% WoW, +62.50% vs Dec 29)

• Gasoline: $4.29 (+2.75% WoW, +45.31% vs Dec 29)

• 3-week diesel change (Mar 9 → Mar 30): +25.09%

• Diesel–gas spread: $1.02 (vs $0.32 baseline)

(Note: Last week's preliminary diesel price of $5.23 settled to $5.18. This week's WoW is calculated from the settled figure.)

WHAT CHANGED THIS WEEK

• Diesel increased 2.51% WoW, down from +2.97% the prior week (calculated from settled $5.18, not the preliminary $5.23)

• Gasoline increased 2.75% WoW, slightly accelerating from +2.36% — flipping the pattern for the first time, with gasoline WoW exceeding diesel WoW

• 52.1% of the total diesel increase since Dec 29 occurred in the last 3 weeks (since Mar 9)

• The diesel–gas spread peaked at $1.02 this week; early W14 data suggests a sharp compression to $0.76, as gasoline WoW (+12.7%) far outpaced diesel (+5.4%). The gasoline repricing wave we flagged last week appears to be arriving.

Interpretation: In isolation, W13 continued the deceleration trend — diesel WoW dropped from +13.0% (W10) → +4.8% (W11) → +3.0% (W12) → +2.5% (W13). But early W14 data already shows diesel at $5.59, a +5.35% WoW reacceleration that breaks the trend and sets a new all-time high, surpassing the June 2022 energy-crisis peak ($5.50). The plateau thesis is not confirmed.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: California ($6.69), Hawaii ($6.44), Washington ($6.37)

• Lowest diesel states: North Dakota ($4.67), Oklahoma ($4.79), Wisconsin ($4.81)

• National spread: $2.02 between highest and lowest states

California posted the largest single-week jump (+$0.54), while Arizona (+$0.41) and Nevada (+$0.33) also saw outsized increases — West Coast states continue to lead. Only 4 states saw WoW decreases (Idaho, Utah, Indiana, Illinois), all modest. All 50 states are now positive YoY, with Oregon leading at +77.4% and Arizona at +$2.65 in absolute terms.

WHAT THIS MEANS

This week told two stories — and the second one matters more.

The W13 data, taken alone, supported a plateau: diesel WoW gains fell for the fourth straight week, gasoline WoW overtook diesel for the first time, and only 4 states declined. A controlled deceleration onto an elevated base.

But early W14 data has already invalidated that. Diesel jumped to $5.59 — a +5.35% WoW reacceleration and a new all-time high, surpassing the June 2022 energy-crisis peak ($5.50). The deceleration from W10–W13 now looks like a pause, not a plateau.

The differences from 2022 are structural:

• The 2022 peak was a sharp supply-shock spike that reversed within weeks

• The current repricing has been a grinding 14-week ascent with no reversal signals — 46 of 50 states still posted WoW increases in W13

• At $5.31, diesel is already 62.5% above Dec 29; at $5.59 (W14 preliminary), it's 71.1% above

The gasoline convergence is now accelerating. The diesel–gas spread peaked at $1.02 in W13 and early W14 data shows it compressing sharply to $0.76, driven by gasoline repricing at more than double diesel's rate (+12.7% vs +5.4% WoW). The "second front" we flagged last week is no longer a signal — it's underway.

The strategic question has shifted again: this is no longer about whether prices plateau at $5.30 — it's about how far above the 2022 peak they go, and whether gasoline is now entering the same repricing cycle diesel began in early March.

METHODOLOGY Aggregated weekly average fuel prices paid by customers; baseline = week of Dec 29, 2025. W14 data is preliminary and subject to settlement revisions.

Diesel prices rose 3.82% week over week, extending a 59.99% increase since year start as weekly gains continue to moderate from their early-March peak.

• Diesel: $5.23 (+3.82% WoW, +59.99% vs Dec 29)

• Gasoline: $4.13 (+1.52% WoW, +39.99% vs Dec 29)

• 3-week diesel change (Mar 2 → Mar 23): +23.14%

• Diesel–gas spread: $1.09 (vs $0.31 baseline)

WHAT CHANGED THIS WEEK

• Diesel increased 3.82% WoW, down from +4.82% the prior week

• Gasoline increased just 1.52% WoW, sharply moderating from +6.59% the prior week

• 50.1% of the total diesel increase since Dec 29 occurred in the last 3 weeks (since Mar 2)

• Diesel WoW (+3.82%) again exceeded gasoline WoW (+1.52%), continuing to widen the spread

Interpretation:

The deceleration trend that began in W12 continued this week — diesel gains have dropped roughly 70% from their W10–W11 peak, and gasoline increases have nearly flattened. Prices are transitioning from active repricing to an elevated plateau.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: Connecticut ($6.65), Washington ($6.33), California ($6.14)

• Lowest diesel states: Montana ($4.82), Oklahoma ($4.87), North Dakota ($4.88)

• National spread: $1.83 between highest and lowest states

Nevada posted the largest single-week jump (+$0.91), while Connecticut (+$0.57) and North Dakota (+$0.35) also saw outsized increases. Only 5 states saw WoW decreases (Virginia, Vermont, Indiana), confirming upward pressure remains broadly distributed. Connecticut leads the nation in YoY increase at +86.0%.

WHAT THIS MEANS

The headline risk has shifted. Four weeks ago, the concern was the speed of the repricing. This week, the concern is where prices settle.

• Diesel WoW gains have dropped from +14.8% (W10) to +3.8% (W13) — a clear deceleration — but on a base that is now 60% above Dec 29

• Gasoline is flattening faster than diesel (+1.5% WoW vs +3.8%), which means the diesel–gasoline spread ($1.09, up from $0.31) is now the primary margin pressure point for diesel-heavy fleets

• 43 of 48 reporting states still posted WoW increases — the repricing is slowing but not reversing

• If next week's diesel WoW drops below +2%, that would confirm a plateau; a reacceleration above +5% would signal a second wave

The strategic question is no longer whether prices are rising — it's whether $5.20+ diesel is the new normal or an overshoot that corrects.

METHODOLOGY Aggregated weekly average fuel prices paid by customers; baseline = week of Dec 29, 2025.

Diesel prices rose 4.82% week over week, extending a 49.31% increase since year start and following two weeks of rapid escalation.

• Diesel: $5.03 (+4.82% WoW, +49.31% vs Dec 29)

• Gasoline: $4.07 (+6.59% WoW, +28.18% vs Dec 29)

• 3-week diesel change (Feb 23 → Mar 16): +36.20%

• Diesel–gas spread: $0.96 (vs $0.20 baseline)

WHAT CHANGED THIS WEEK

• Diesel increased 4.82% WoW, down from +13.16% the prior week

• Gasoline increased 6.59% WoW, also moderating from prior double-digit gains

• 80.5% of the total diesel increase since Dec 29 occurred after Feb 23

• Gasoline WoW (+6.59%) exceeded diesel WoW (+4.82%) for the first time since the acceleration began

Interpretation:

Weekly increases have slowed significantly—diesel gains dropped by roughly two-thirds from peak—but prices remain elevated following a rapid repricing period.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: Washington ($6.37), Hawaii ($6.23), Connecticut ($6.22)

• Lowest diesel states: North Dakota ($4.56), South Dakota ($4.75), Nebraska ($4.76)

• National spread: $1.81 between highest and lowest states

Price pressure remains geographically concentrated, with coastal and Northeast states sustaining the highest absolute costs. The Northeast (RI, ME, CT) is now posting the steepest weekly gains, suggesting a lagged repricing wave moving east.

WHAT THIS MEANS

Fuel prices have moved through a three-phase pattern:

1. Stability (through mid-Feb): single-digit weekly changes, gradual drift upward

2. Acceleration (Mar 2 → Mar 9): sustained double-digit weekly increases

3. Moderation (Mar 16): mid-single-digit increases on a higher base

Prices are no longer just rising — they've reset higher:

• Diesel is +49.31% vs baseline

• The diesel–gasoline gap has widened from $0.20 to $0.96

• Cost pressure remains highest for diesel-heavy operations and high-cost states

• All 50 states have higher diesel prices than a year ago (+48.48% YoY nationally)

METHODOLOGY Aggregated weekly average fuel prices paid by customers; baseline = week of Dec 29, 2025.

Diesel prices surged 13.16% week over week — the second consecutive week of double-digit gains — pushing the cumulative increase since Dec 29 to 42.45%.

• Diesel: $4.80 (+13.16% WoW, +42.45% vs Dec 29)

• Gasoline: $3.82 (+10.76% WoW, +20.26% vs Dec 29)

• 3-week diesel change (Feb 16 → Mar 9): +33.68%

• Diesel–gas spread: $0.98 (vs $0.20 baseline)

WHAT CHANGED THIS WEEK

• Diesel increased 13.16% WoW, slightly down from +14.83% the prior week but still in double-digit territory

• Gasoline increased 10.76% WoW, roughly in line with the prior week's +10.34%

• 77.3% of the total diesel increase since Dec 29 has occurred in just the last two weeks

• All 50 states saw diesel prices rise — no state was spared

Interpretation:

This is now the second straight week of double-digit diesel gains. The acceleration that began in early March is sustaining, not fading. Prices have moved from gradual drift to a full repricing event.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: Washington ($5.93), California ($5.91), Hawaii ($5.82)

• Lowest diesel states: North Dakota ($4.42), Montana ($4.45), Nebraska ($4.59)

• National spread: $1.51 between highest and lowest states

• 28 states above national average, 22 below

Biggest WoW movers: Idaho (+$0.44), Utah (+$0.43), Vermont (+$0.40). No state saw a decline — the repricing is universal across all 50 states.

WHAT THIS MEANS

The fuel market is now clearly in an acceleration phase. Two back-to-back weeks of 13–15% diesel increases have reshaped the cost landscape:

• Diesel has gained over 42% vs the Dec 29 baseline in just 10 weeks

• The diesel–gas spread has widened from $0.20 to $0.98 — nearly 5× the baseline

• The pace of increase has not yet moderated, suggesting the repricing may have further to run

• With 100% of states seeing increases, there is no geographic safe harbor this week

Diesel prices exploded 14.83% week over week — the largest single-week increase in the dataset — catapulting the cumulative gain since Dec 29 to 25.88%.

• Diesel: $4.24 (+14.83% WoW, +25.88% vs Dec 29)

• Gasoline: $3.45 (+10.34% WoW, +8.58% vs Dec 29)

• 3-week diesel change (Feb 9 → Mar 2): +19.71%

• Diesel–gas spread: $0.80 (vs $0.20 baseline)

WHAT CHANGED THIS WEEK

• Diesel increased 14.83% WoW, a massive escalation from +2.88% the prior week

• Gasoline increased 10.34% WoW, also jumping sharply from +2.46% the prior week

• 74.6% of the total diesel increase since Dec 29 occurred in this single week and the one prior

• All 50 states saw diesel prices rise

Interpretation:

This week marks the inflection point. After two months of low-single-digit weekly changes, diesel prices suddenly jumped nearly 15% in a single week. Gasoline followed with a 10%+ move. Something fundamental shifted in the market during the last week of February — the gradual drift is over and a rapid repricing is underway.

WHERE PRESSURE IS HIGHEST

• Highest diesel states: California ($5.76), Washington ($5.63), Hawaii ($5.57)

• Lowest diesel states: Montana ($4.08), North Dakota ($4.19), Minnesota ($4.36)

• National spread: $1.67 between highest and lowest states

• 25 states above national average, 25 below — an even split

Biggest WoW movers: North Carolina (+$0.74), South Carolina (+$0.67), Virginia (+$0.67). The Southeast posted the largest dollar increases this week, with the Carolinas and Virginia leading. Biggest declines: North Dakota (−$0.36), Oklahoma (−$0.34), Minnesota (−$0.31) — Plains states bucked the trend.

WHAT THIS MEANS

This is the week the market broke. The data tells a clear before-and-after story:

• Before (Jan–late Feb): diesel WoW changes ranged from −0.4% to +3.2% — normal weekly noise

• After (Mar 2): +14.83% in a single week, with gasoline following at +10.34%

• The diesel–gas spread quadrupled from $0.20 to $0.80 in one week, signaling that diesel-specific supply factors are driving this move

• The geographic pattern is unusual — the Southeast led increases while Plains states actually declined, suggesting regional supply disruptions rather than a uniform demand shock

METHODOLOGY Aggregated weekly average fuel prices paid by customers; baseline = week of Dec 29, 2025.