Earlier editions: 2026-09
Title 13 — UTILITIES›Chapter 13.30 — WATER EFFICIENT LANDSCAPE ORDINANCE
Colton Municipal Code Appendix A Reference Evapotranspiration (ETo) Table
Colton Municipal Code · 2026-10 edition · updated 2026-10-04 · Colton
Cite as: Colton Municipal Code Appendix A · Text as of 2026-10-04
Appendix A - Reference Evapotranspiration (ETo) Table*
| County and City SAN BERNARDINO | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual ETo |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Baker | 2.7 | 3.9 | 6.1 | 8.3 | 10.4 | 11.8 | 12.2 | 11.0 | 8.9 | 6.1 | 3.3 | 2.1 | 86.6 |
| Barstow NE | 2.2 | 2.9 | 5.3 | 6.9 | 9.0 | 10.1 | 9.9 | 8.9 | 6.8 | 4.8 | 2.7 | 2.1 | 71.7 |
| Big Bear Lake | 1.8 | 2.6 | 4.6 | 6.0 | 7.0 | 7.6 | 8.1 | 7.4 | 5.4 | 4.1 | 2.4 | 1.8 | 58.6 |
| Chino | 2.1 | 2.9 | 3.9 | 4.5 | 5.7 | 6.5 | 7.3 | 7.1 | 5.9 | 4.2 | 2.6 | 2.0 | 54.6 |
| Crestline | 1.5 | 1.9 | 3.3 | 4.4 | 5.5 | 6.6 | 7.8 | 7.1 | 5.4 | 3.5 | 2.2 | 1.6 | 50.8 |
| Lake Arrowhead | 1.8 | 2.6 | 4.6 | 6.0 | 7.0 | 7.6 | 8.1 | 7.4 | 5.4 | 4.1 | 2.4 | 1.8 | 58.6 |
| Lucerne Valley | 2.2 | 2.9 | 5.1 | 6.5 | 9.1 | 11.0 | 11.4 | 9.9 | 7.4 | 5.0 | 3.0 | 1.8 | 75.3 |
| Needles | 3.2 | 4.2 | 6.6 | 8.9 | 11.0 | 12.4 | 12.8 | 11.0 | 8.9 | 6.6 | 4.0 | 2.7 | 92.1 |
| Newberry Springs | 2.1 | 2.9 | 5.3 | 8.4 | 9.8 | 10.9 | 11.1 | 9.9 | 7.6 | 5.2 | 3.1 | 2.0 | 78.2 |
| San Bernardino | 2.0 | 2.7 | 3.8 | 4.6 | 5.7 | 6.9 | 7.9 | 7.4 | 5.9 | 4.2 | 2.6 | 2.0 | 55.6 |
| Twentynine Palms | 2.6 | 3.6 | 5.9 | 7.9 | 10.1 | 11.2 | 11.2 | 10.3 | 8.6 | 5.9 | 3.4 | 2.2 | 82.9 |
| Victorville | 2.0 | 2.6 | 4.6 | 6.2 | 7.3 | 8.9 | 9.8 | 9.0 | 6.5 | 4.7 | 2.7 | 2.1 | 66.2 |
* The values in this table were derived from:
California Irrigation Management Information System (CIMIS);
Reference EvapoTranspiration Zones Map, UC Dept. of Land, Air and Water Resources and California Dept. of Water Resources 1999;
Reference Evapotranspiration for California, University of California, Department of Agriculture and Natural Resources (1987) Bulletin 1922; and
Determining Daily Reference Evapotranspiration, Cooperative Extension UC Division of Agriculture and Natural Resources (1987), Publication Leaflet 21426.
(Ord. No. O-12-15, Att.(App. A), 1-16-2016)
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