Records Set Near Tropical Cyclones

A record is a value that beat every earlier value of its station in the site's record ledger: for its calendar day (daily), for its month (monthly) or for the whole history of the station (all-time). A record set at a station on a given day is linked to a tropical cyclone when one of the storm's best track positions dated that day or the day before (UTC) lies within 500 km (311 mi) of the station, measured along the earth's surface. The day before counts because a daily rain total covers a local observation day that often ends in the morning, so the rain of a storm that passed the day before is often reported on the next day. 500 km (311 mi) is the radius the tropical cyclone rainfall literature commonly uses. The remnant and extratropical stages of a storm are part of its track and count.

The storms are the named tropical cyclones with a known peak wind in the IBTrACS best track archive, the ones with a storm page on this site, from the 1945 to 2027 seasons (5,425 storms). Records are counted the way the daily ledger counts them: one per observation, at the broadest timescale it broke (all-time, else monthly, else daily), and a tie of an earlier record is left out. In the lists of storms a record within reach of two storms counts for each of them; in the totals and in the decade table it counts once, for the closer storm. A southern hemisphere season runs from July to June and carries the year in which it ends, so the season under way now is the 2027 season.

A station enters the ledger only once it has 30 years of data for an element, so records, and links to storms, start 30 years after a station's first year. Only stations in countries with an ISO country code are counted, as everywhere on the site.

23,068 stations have a standing all-time daily rain record and at least 5 storms with a best track position within 500 km (311 mi) of them in the 1945 to 2027 seasons. Their wettest day on record can be checked against the tracks at 7,000 of them: at 13,554 the record was set in the station's first 30 years of rain data, before the ledger starts there, and at 2,514 before the archive holds every named storm of the basins that reach the station, so no link can exist. The archive keeps named storms only and the basins began naming in different years, so it is complete for North Atlantic from 1950, Eastern North Pacific from 1960, Western North Pacific from 1945, North Indian from 2005, South Indian from 1971 and South Pacific from 1970; a station is checked from the latest of these for the basins that bring it at least a tenth of its storms.

At 1,677 of the 7,000 stations checked (24%), the wettest day on record came while a storm was within 500 km (311 mi), on that day or the day before.

Countries with at least 20 stations checked and at least one wettest day that came with a storm. In Netherlands, Norway, Spain and Sweden no wettest day on record came with a storm: the remnants of storms that turned into ordinary lows pass within 500 km (311 mi) of their stations often enough to meet the rule, but bring them no record rain.

The 25 storms with the most daily, monthly and all-time rain records set within 500 km (311 mi) of their track, of 2,730 storms with at least one. The all-time column counts the records that beat every earlier value of their station; the station column counts the stations with at least one of these records. A storm whose track crosses land with many long running stations can collect many records, so the list also reflects where the stations are.

Rain records set within 500 km (311 mi) of a track, by the decade of the storm's season and the basin where its track begins, each record counted once with its closest storm. The raw counts follow the station network: the number of stations with 30 or more years of data grew over the period, most of all in the United States, and storms that reach land where stations are dense collect far more records than storms over the open ocean. Records per storm divide the count by every storm of the decade and basin, so they show how often storms came near long running stations, not how wet the storms were. A decade still running is marked with its last season.

Each cell gives the storms of the decade and basin, and in brackets the storms with at least one rain record set within 500 km (311 mi) of their track.

120 of the 262 storms of the 2024 to 2027 seasons had at least one rain record set within 500 km (311 mi) of their track. Daily data from stations outside the United States arrive days to weeks late, so these counts can still rise, and the newest track positions are provisional in IBTrACS.

75,187 temperature records were set within 500 km (311 mi) of the track of 2,482 storms of the 1980 season onward, each counted once with its closest storm. The most common type is the lowest daily maximum (a cool day), with 29,528 (39%). A record low maximum is a day that stayed cooler than on that calendar day, month or ever before; a record high minimum is a night that stayed warmer.

Closeness in space and time, not cause. A record within 500 km (311 mi) of a track on the right day can come from another weather system: a front, a monsoon trough or a thunderstorm far from the storm's rain. A storm can also bring heavy rain beyond 500 km (311 mi), which this rule does not count.

The station network is densest in the United States, Japan and Australia, and most tropical cyclone coasts have few stations with long records, so the counts say most about those three countries. Tracks before the satellite era, about 1970, miss some weaker or remote storms.

Daily data from stations outside the United States arrive days to weeks late, so recent storms gain records over time. Daily values belong to local observation days, so the matching window is two days wide, and on the day after a storm passed another system may be responsible.

For the storms themselves, their strength and how fast they intensified, see storm extremes.