| Climate Precipitation Winds Currents Destinations |
The two groups of islands are two sides of the same coin — they share a geological and social history, and are separated only by national border. Both are world-class cruising destinations, attracting boats from everywhere, yet retain get-away-from-it-all laid back culture. Each has its unique communities with their sometimes peculiar heritage, as well as their resident (or semi-resident) bazillionaires and celebrities. It’s always nice to know someone else bought a piece of paradise.
However, there is that border to consider.
Cruising through these regions can take all summer, or longer. The population of the San Juan islands drops to a third or less during the fall-spring period. The Gulf Islands are not quite so homogenous with some islands being mostly permanent residents and others primarily tourists and migrating summer people, but over all about half the population stays year-’round. If you visit during the off-season be prepared to find some businesses closed.
Climate
Tucked in behind the Olympic Peninsula and Vancouver Island, the islands are in rain shadow and generally protected from the open ocean winds and seas. Forming the southern boundary of the Georgia Strait, the waters are somewhat cooler than the norther end of the basin. The narrow, protected channels seem insulated even from the heavier weather of the Strait, however, and mild lazy sailing may be the order of the day inside the protection of the islands while just outside strong winds are whipping up waves.
The following climatic data is from Environment Canada. Climate data for the San Juans (or most anywhere else in the USA) is no longer available from the US government, but should be similar to the Canadian Gulf Islands.
| May | Jun | Jul | Aug | Sep | |
|---|---|---|---|---|---|
| Gabriola Island | 16.6/6.6 (61.8/43.8 F) |
19.3/9.6 (66.7/49.3 F) |
22.2/11.4 (72.0/52.5 F) |
22.3/11.2 (72.1/52.1 F) |
19.2/8.4 (66.6/47.1 F) |
| St. Mary’s Lake, Saltspring Is. | 16.8/8.5 (62/47 F) |
19.7/11.1 (67/52 F) |
22.4/13.3 (72/56 F) |
22.5/13.6 (72/56 F) |
19.2/11.2 (67/52 F) |
| Mayne Is. | 17.3/7.2 (63/45 F) |
20.0/9.4 (68/49 F) |
22.5/11.0 (72/55 F) |
22.6/11.1 (73/56 F) |
19.8/9.0 (68/48 F) |
Precipitation, Fog, and Clouds
The rainy season in the region is from October to April, but regular precipitation throughout the summer months is normal. The rain shadow effects of the Olympic Mountains and Vancouver Islan are particularly pronounced in the San Juan and Gulf Islands, resulting in a very high percentage of clear sunny days in the summer. For this reason the region is particularly attractive to cruisers and other tourists; some may feel the over-population during the summer months more a drawback than the less sunny rainy season.
The extra-clear skies tends to result in extra-warm temps over the land, and that leads to warm air moving over cold water – resulting in sometime thick and billowy convection fog. This feature is particularly noted in the San Juans, usually dawn fogs which burn off around mid-day.
| May | Jun | Jul | Aug | Sep | |
|---|---|---|---|---|---|
| Gabriola Island | 44.9 mm (1.8″) | 40.9 mm (1.6″) | 26.0 mm (1.0″) | 28.2 mm (1.1″) | 38.5 mm (1.5″) |
| St. Mary’s Lake, Saltspring Is | 44.1 mm (1.7″) | 38.8 mm (1.5″) | 24.7 mm (1.0″) | 30.0 mm (1.2″) | 36.5 mm (1.4″) |
| Mayne Is. | 40.7 mm (1.6″) | 35.2 mm (1.4″) | 22.1 mm (0.9″) | 28.1 mm (1.1″) | 32.6 mm (1.3″) |
Winds
Throughout the Gulf and San Juan Islands the over-arching wind patterns are from the SE or the NW, but altered by the local topography, sometimes dramatically. What this means in practice is most winds are gap winds, sometimes sped up by being channeled into new directions. There are locally traditional variations – for example in Bellingham Bay the regional south-easterlies are south-westerlies, and quite reliable during the warm summer months.
Currents
More than half of the water which pours into the Georgia Basin washes through the channels of the San Juan and Gulf Islands and the waterway between them. Needless to say the currents can sometimes be challenging, especially when complicated by wind-over-current conditions.
Even so, the only portions of the region requiring exceptional care regarding current are the passes from the inside of the Gulf Islands into Georgia Strait, and north through Dodd Narrows to Nanaimo. Gabriola Pass, Porlier Pass, and Active Pass, plus Dodd Narrows, can each have extreme tidal currents. During summer months traffic jams will form on either side of the passes just before slack as boats arrive early; this is especially true at Dodd Narrows, and locals often set out chairs to watch the jostling and the regular unplanned contact between boats as the turbulent currents fool the less wary helmscritters. The boatyards of Nanaimo are very familiar with such repairs, and will be happy to take your cruising kitty from you. Be aware that these very narrow waters have a lot of traffic, and vessels traveling with will have much less control than vessels traveling against the current. The best passage in my opinion is to arrive early for slack when the current will be switching from foul to favourable, and nosing up against that current before it has quite slacked.
Destinations
The sheer number and complexity of these two regions, each with hundreds of things to do and see, means they deserve their own pages.
Bibliography:
- Environment Canada (2002). Canadian Climate Normals 1971-2000. Retrieved 7 December 2008 from Environment Canada. Website: http://www.climate.weatheroffice.ec.gc.ca/climate_normals/stnselect_e.html
- San Juan Sailing.com. San Juan Islands Cruising Guide Retrieved 9 December 2008 from Google Cache: cache link
