Every wonder how we get the terms regarding rain and rainfall rates. This chart
should explain it all.
|
Drops Per sq. ft. per sec. |
Diameter of Drops (mm) |
Intensity (cm. per hr.) |
Intensity (in. per hr.) |
| Cloudburst |
113 |
2.85 |
10.24 |
4.00 |
| Excessive Rain |
76 |
2.40 |
4.01 |
1.60 |
| Heavy Rain |
46 |
2.05 |
1.54 |
.60 |
| Moderate Rain |
46 |
1.60 |
0.38 |
.15 |
| Light Rain |
26 |
1.24 |
0.10 |
.04 |
| Drizzle |
14 |
.96 |
0.025 |
.01 |
| Mist |
2,510 |
.10 |
0.018 |
.002 |
| Fog |
6,264,000 |
.01 |
0.012 |
.005 |
Here's a great little trick sent to me by Sandy:
Keep a small mirror in your instrument screen or other sheltered outdoor
space so that it'll be at ambient temperature. Expose it to the sky for
half a minute or so. One mm is the threshold between drizzle and rain. The
mirror also helps to distinguish hail, ice pellets, snow grains, and
freezing precip.