Weather Records Against Chance: Puerto Rico [United States]
In the 2020s, record highs ran at 1.95 times the number expected by chance in Puerto Rico [United States] (1951-1980: 0.69) and record lows at 0.37 times (1951-1980: 0.77).
Data as of . Last revised (2026-10-16).
Key Facts
- In the 2020s so far (to 2026-10-16), 1,973 record highs of daily temperature were observed in Puerto Rico [United States] against 1,013 expected by chance, 1.95 times the expected number. In 1951-1980 the same measure was 0.69.
- In the 2020s so far (to 2026-10-16), 379 record lows of daily temperature were observed in Puerto Rico [United States] against 1,013 expected by chance, 0.37 times the expected number. In 1951-1980 the same measure was 0.77.
- By type in the 2020s in Puerto Rico [United States], observed over expected was 1.02 for record highs of the daily maximum, 0.62 for record lows of the daily maximum, 2.88 for record highs of the daily minimum, 0.13 for record lows of the daily minimum.
- In 2026 (to 2026-10-16), record highs ran at 1.78 times the expected number in Puerto Rico [United States] and record lows at 0.27 times.
- Expected counts assume a stable climate: the k-th year of a station's record sets a record on a given day with chance 1 in k.
- Readings are whole tenths of a degree and ties are not records, so strict records run below the naive expectation even without a trend. This page compares with the 1951-1980 level and not with 1.
How to Read This Page
In a stable climate, the k-th year of a station's record sets a record on a given day with chance 1 in k. Adding that chance up over every station, day and year gives the number of daily records expected without any change. The site records a station's records from its 31st year of data, so a station-year counts from there.
Readings are whole tenths of a degree, and a tie is not a record, so strict records run below the naive expectation even without a trend. For that reason the charts compare observed over expected with the 1951-1980 level (0.69 for record highs and 0.77 for record lows in this data), drawn as a dashed line, and not with 1.
Record highs and record lows combine the daily maximum and the daily minimum temperature. The level for each is the average of the two levels in the data. A value above the dashed line means more records than in 1951-1980; below it means fewer. The numbers show what was observed and how it compares. They do not say why.
Observed Over Expected by Year
Highs and lowsRecord highs
| Year | record highs observed over expected |
|---|---|
| 2026 | 1.78 |
Record lows
| Year | record lows observed over expected |
|---|---|
| 2026 | 0.27 |
The charts start in 2026. 95 earlier years are left out because too few records were expected from the few stations with a long enough record. The data download has every year.
Observed and Expected Records by Year
Counts| Year | Record highs observed | Record highs expected | Record lows observed | Record lows expected |
|---|---|---|---|---|
| 2026 | 191 | 107 | 29 | 107 |
Observed Over Expected by Decade
Record highs
| Decade | record highs observed over expected |
|---|---|
| 1930s | 0.54 |
| 1940s | 1.05 |
| 1950s | 0.71 |
| 1960s | 0.68 |
| 1970s | 0.53 |
| 1980s | 1.12 |
| 1990s | 1.09 |
| 2000s | 1.14 |
| 2010s | 1.55 |
| 2020s | 1.95 |
Record lows
| Decade | record lows observed over expected |
|---|---|
| 1930s | 0.87 |
| 1940s | 0.68 |
| 1950s | 0.67 |
| 1960s | 0.74 |
| 1970s | 0.93 |
| 1980s | 0.80 |
| 1990s | 1.04 |
| 2000s | 0.75 |
| 2010s | 0.69 |
| 2020s | 0.37 |
| Decade | Highs observed | Highs expected | Highs observed over expected | Lows observed | Lows expected | Lows observed over expected |
|---|---|---|---|---|---|---|
| 1930s | 408 | 762 | 0.54 | 660 | 762 | 0.87 |
| 1940s | 1,434 | 1,360 | 1.05 | 928 | 1,360 | 0.68 |
| 1950s | 947 | 1,335 | 0.71 | 898 | 1,335 | 0.67 |
| 1960s | 1,491 | 2,193 | 0.68 | 1,623 | 2,193 | 0.74 |
| 1970s | 1,073 | 2,041 | 0.53 | 1,890 | 2,041 | 0.93 |
| 1980s | 2,495 | 2,231 | 1.12 | 1,780 | 2,231 | 0.80 |
| 1990s | 3,075 | 2,817 | 1.09 | 2,934 | 2,817 | 1.04 |
| 2000s | 2,810 | 2,462 | 1.14 | 1,837 | 2,462 | 0.75 |
| 2010s | 2,824 | 1,817 | 1.55 | 1,255 | 1,817 | 0.69 |
| 2020s | 1,973 | 1,013 | 1.95 | 379 | 1,013 | 0.37 |
By Record Type, 2020s
Against the 1951-1980 level| Record type | Observed | Expected | Observed over expected | 1951-1980 level |
|---|---|---|---|---|
| Record high maximum temperature | 518 | 507 | 1.02 | 0.69 |
| Record low maximum temperature | 313 | 507 | 0.62 | 0.87 |
| Record high minimum temperature | 1,455 | 506 | 2.88 | 0.69 |
| Record low minimum temperature | 66 | 506 | 0.13 | 0.67 |
The 2020s are not over: this decade runs to 2026, up to 2026-10-16.
Download the Data
Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-16. Observed records are computed by this site from daily maximum and minimum temperature. Expected counts assume a stable climate.