Monthly Attribution Overview – March 2026

An analysis of how climate change boosted United States temperatures in March 2026

Using Climate Central’s Climate Shift Index (CSI) tool to measure the impact of climate change on daily temperatures across the United States, as well as NOAA’s Applied Climate Information System (ACIS) to find daily temperature information, we have compiled a high-level overview of how climate change has affected temperature trends in March in cities across the United States. (Dataset downloadable as Excel workbook here.)

1. High-level findings

• Overall, the U.S. saw unprecedented temperatures in March, with an average anomaly — or difference from normal — of 5.8°F across 192 cities.

• While the eastern U.S. experienced above-average temperatures, a record-shattering heat wave anchored over the West Coast drove the overall national trend.

• Eighty cities experienced one of their top five warmest March temperatures on record. On average, stations have data dating back to 1893.

• Elevated Climate Shift Index values occurred in eight out of nine U.S. Climate Regions, including the Southwest, West, Northern Rockies and Plains, South, Southeast, Upper Midwest, Ohio Valley, and Northeast.

• March 2026 was exceptionally warm, mirroring the long-term March warming trends, which show that nearly all cities analyzed have warmed since 1970, consistent with findings from Climate Central’s 2025 Winter Package. 

Figure 1. Temperature anomalies (differences from normal) for March 2026 relative to 1991-2020 normals. Analysis based on threaded ACIS station-level data.

Figure 2. Statewide average days with a CSI level 2 or higher for March 2026. Analysis based on ERA5 data.

2. Local temperature anomaly analysis

• The average temperature anomaly — or difference from normal — across the 192 cities analyzed was 5.8°F. 

• March temperatures were overwhelmingly warm, with 188 cities recording warmer-than-average conditions, compared to four cities that experienced cooler-than-average conditions.

• Temperatures were elevated across many areas in the Southwest, West, Northern Rockies and Plains, South, Southeast, and Upper Midwest, Ohio Valley, and Northeast. Southwest stood out as the warmest region, with average temperatures more than 10.4°F above normal. 

• Thirty-three cities experienced their hottest March on record.

• The most unusually warm city in March was Phoenix, which was 12.5°F warmer than usual.

• The most unusually cold region was the Northwest, with average temperature anomalies of -1.8°F. 

• Of the 192 locations analyzed, most (188)showed long-term warming trends for March, indicating that these cities have warmed on average since 1970.

• Wheeling, West Virginia, experienced the greatest increase, with average March temperatures 11.7°F warmer than in 1970.

Table 1. ACIS stations with the highest March 2026 temperature anomaly.

Table 2. ACIS stations with the fastest warming March since 1970.

3. Local Climate Shift Index analysis

• Flagstaff, Arizona, had 28 days at or above CSI 2 in March, indicating that temperatures on those days were made at least two times more likely because of climate change.

• 111 cities across the country experienced at least a week's worth of days at or above CSI 2.

• On average, cities in the Southwest experienced the highest number of days (25)with a CSI of 2 or above.

Table 3. ACIS stations with the highest number of days at or above CSI 2 during March 2026.

METHODOLOGY

Calculating the Climate Shift Index

All Climate Shift Index (CSI) levels reported in this brief are based on daily average temperatures and ERA5 data. See the frequently asked questions for details on computing the Climate Shift Index, including a summary of the multi-model approach described in Gilford et al. (2022).

City analysis

We analyzed 192 Applied Climate Information System (ACIS) stations associated with U.S. cities. For each city, we found the CSI time series from the nearest 0.25° grid cell. We calculated the number of days at CSI levels 2, 3, 4, and 5. We used ACIS data to find the average monthly temperatures, temperature anomalies (compared to 1991-2020 normals), and precipitation information, and to derive average monthly warming trends for each city.

Regions

Regions are defined by NOAA’s National Centers for Environmental Information climate regions.