Qualicum Beach
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Qualicum Beach clear sky chart from 2005-11-06 to 2024-01-12.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	15% 10% 4 8% 7% 4 5% 5% 5% 6% 30%	74698
	Night	16% 10% 4 8% 7% 4 5% 5% 5% 6% 30%	75036
Transparency	Day	36% 39% 12% 10% 4 1	74382
	Night	37% 38% 10% 10% 4 1	74870
Seeing	Day	19% 6% 18% 26% 23% 8%	14465
	Night	24% 6% 17% 26% 21% 6%	22668

By Month

Percentage Cloud Cover NW (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	23% 15% 7% 11% 9% 5% 5% 4 4 3 14%	1329
	11th to 20th	Day	17% 14% 6% 10% 9% 5% 7% 6% 6% 8% 13%	1269
	21st to end	Day	18% 17% 7% 11% 9% 5% 6% 7% 6% 5% 10%	1549
February	1st to 10th	Day	20% 15% 5% 10% 9% 4 6% 6% 5% 6% 14%	1620
	11th to 20th	Day	17% 17% 5% 9% 7% 4 5% 5% 5% 5% 20%	1575
	21st to end	Day	14% 13% 6% 9% 9% 4 6% 6% 5% 8% 19%	1332
March	1st to 10th	Day	12% 15% 4 10% 8% 5% 7% 7% 7% 6% 18%	1883
	11th to 20th	Day	17% 12% 4 10% 9% 5% 6% 6% 5% 6% 19%	1980
	21st to end	Day	18% 14% 5% 9% 8% 5% 6% 5% 5% 5% 21%	2184
April	1st to 10th	Day	17% 13% 6% 10% 9% 4 6% 5% 5% 6% 19%	2160
	11th to 20th	Day	15% 12% 6% 10% 9% 5% 6% 5% 5% 5% 24%	2291
	21st to end	Day	17% 10% 5% 8% 7% 4 5% 6% 6% 6% 25%	2340
May	1st to 10th	Day	12% 8% 3 6% 8% 5% 6% 6% 7% 8% 32%	2515
	11th to 20th	Day	15% 9% 3 7% 6% 4 5% 5% 6% 8% 31%	2477
	21st to end	Day	14% 8% 4 7% 7% 4 7% 6% 6% 7% 30%	2870
June	1st to 10th	Day	17% 9% 4 8% 7% 5% 6% 5% 5% 6% 27%	2700
	11th to 20th	Day	12% 8% 5% 9% 8% 4 7% 6% 7% 8% 26%	2700
	21st to end	Day	10% 7% 4 7% 6% 4 5% 5% 6% 7% 38%	2700
July	1st to 10th	Day	11% 5% 3 6% 5% 3 4 5% 5% 7% 45%	2700
	11th to 20th	Day	7% 5% 2 4 4 3 4 4 5% 8% 53%	2700
	21st to end	Day	6% 3 1 4 4 2 3 4 5% 8% 60%	2882
August	1st to 10th	Day	8% 5% 1 5% 5% 2 3 4 5% 7% 55%	2418
	11th to 20th	Day	5% 5% 2 4 4 3 4 4 6% 8% 55%	2298
	21st to end	Day	7% 6% 2 7% 5% 3 5% 6% 6% 9% 44%	2570
September	1st to 10th	Day	9% 5% 2 5% 5% 3 4 5% 5% 8% 49%	2160
	11th to 20th	Day	15% 7% 2 6% 5% 4 4 4 5% 6% 41%	2087
	21st to end	Day	16% 7% 3 7% 7% 3 4 5% 6% 6% 37%	1943
October	1st to 10th	Day	17% 10% 3 8% 6% 3 4 5% 5% 7% 33%	1800
	11th to 20th	Day	21% 9% 4 7% 7% 4 5% 5% 6% 7% 24%	1800
	21st to end	Day	19% 10% 5% 9% 8% 4 6% 5% 6% 6% 23%	1819
November	1st to 10th	Day	21% 14% 6% 9% 8% 6% 6% 6% 5% 4 17%	1488
	11th to 20th	Day	18% 13% 5% 8% 7% 5% 7% 5% 5% 5% 21%	1520
	21st to end	Day	21% 15% 5% 10% 8% 3 6% 5% 5% 5% 18%	1520
December	1st to 10th	Day	16% 17% 8% 9% 6% 4 6% 5% 4 5% 21%	1392
	11th to 20th	Day	23% 17% 7% 10% 9% 6% 6% 4 4 4 11%	1685
	21st to end	Day	24% 16% 6% 12% 9% 4 6% 5% 4 4 12%	2442
January	1st to 10th	Night	21% 15% 5% 9% 8% 5% 6% 5% 5% 5% 16%	2836
	11th to 20th	Night	21% 12% 6% 12% 9% 4 6% 5% 5% 6% 15%	2730
	21st to end	Night	18% 15% 5% 9% 8% 4 6% 6% 5% 6% 17%	2804
February	1st to 10th	Night	19% 14% 4 9% 8% 5% 6% 5% 4 5% 21%	2340
	11th to 20th	Night	17% 13% 4 7% 7% 4 5% 5% 4 6% 27%	2272
	21st to end	Night	16% 14% 5% 8% 7% 4 4 5% 5% 5% 26%	1924
March	1st to 10th	Night	14% 11% 5% 7% 7% 5% 6% 6% 7% 7% 26%	2073
	11th to 20th	Night	15% 9% 3 7% 7% 5% 7% 7% 7% 7% 26%	1979
	21st to end	Night	15% 11% 4 9% 8% 6% 7% 6% 5% 6% 23%	2172
April	1st to 10th	Night	16% 10% 4 9% 8% 3 5% 6% 6% 8% 25%	1800
	11th to 20th	Night	15% 11% 4 6% 6% 4 6% 5% 6% 7% 29%	1615
	21st to end	Night	15% 9% 4 8% 7% 3 5% 5% 6% 8% 28%	1620
May	1st to 10th	Night	11% 7% 4 6% 6% 3 6% 5% 4 6% 41%	1445
	11th to 20th	Night	13% 7% 2 7% 6% 4 6% 6% 8% 10% 31%	1416
	21st to end	Night	11% 6% 3 7% 6% 5% 5% 6% 6% 8% 36%	1402
June	1st to 10th	Night	14% 7% 4 7% 6% 3 5% 5% 6% 7% 36%	1260
	11th to 20th	Night	12% 7% 4 7% 7% 3 6% 5% 5% 9% 34%	1260
	21st to end	Night	6% 5% 3 6% 6% 3 6% 6% 7% 10% 42%	1260
July	1st to 10th	Night	7% 6% 2 4 5% 3 5% 5% 5% 7% 52%	1260
	11th to 20th	Night	5% 3 2 3 4 3 4 4 5% 9% 59%	1260
	21st to end	Night	3 2 2 4 3 2 2 5% 4 5% 67%	1433
August	1st to 10th	Night	6% 5% 2 4 3 3 3 4 3 7% 59%	1518
	11th to 20th	Night	4 3 2 3 4 2 3 5% 6% 8% 59%	1602
	21st to end	Night	8% 4 2 4 4 4 4 5% 6% 9% 49%	1785
September	1st to 10th	Night	6% 4 2 5% 4 3 3 4 4 6% 59%	1800
	11th to 20th	Night	14% 7% 3 6% 6% 4 4 5% 4 6% 41%	1872
	21st to end	Night	15% 8% 3 6% 5% 3 4 5% 4 6% 41%	2016
October	1st to 10th	Night	15% 8% 3 6% 5% 3 4 4 4 6% 41%	2160
	11th to 20th	Night	20% 9% 3 7% 7% 4 5% 4 5% 6% 32%	2160
	21st to end	Night	19% 9% 3 8% 7% 3 5% 4 6% 6% 30%	2534
November	1st to 10th	Night	22% 11% 4 8% 8% 4 7% 6% 6% 5% 20%	2590
	11th to 20th	Night	20% 10% 5% 9% 8% 5% 6% 4 5% 6% 22%	2660
	21st to end	Night	20% 12% 5% 9% 8% 4 7% 5% 4 5% 20%	2660
December	1st to 10th	Night	17% 14% 6% 9% 8% 5% 6% 5% 5% 5% 20%	2784
	11th to 20th	Night	23% 17% 7% 12% 8% 4 6% 4 4 4 12%	3520
	21st to end	Night	25% 14% 5% 10% 8% 4 5% 5% 5% 4 14%	5214

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	50% 40% 4 5% 1	1329
	11th to 20th	Day	42% 45% 6% 5% 1	1269
	21st to end	Day	49% 40% 5% 5% 1	1549
February	1st to 10th	Day	48% 39% 7% 5% 1	1620
	11th to 20th	Day	42% 40% 7% 8% 3	1584
	21st to end	Day	42% 38% 9% 8% 3 1	1332
March	1st to 10th	Day	44% 39% 9% 7% 2	1883
	11th to 20th	Day	43% 37% 11% 8% 2 1	1980
	21st to end	Day	43% 37% 12% 7% 1	2184
April	1st to 10th	Day	43% 39% 10% 7% 2	2160
	11th to 20th	Day	39% 36% 10% 8% 7% 1	2291
	21st to end	Day	38% 38% 11% 9% 4	2340
May	1st to 10th	Day	35% 39% 14% 10% 3	2515
	11th to 20th	Day	32% 39% 13% 13% 3	2480
	21st to end	Day	37% 39% 13% 9% 2	2871
June	1st to 10th	Day	38% 39% 10% 8% 3 2	2700
	11th to 20th	Day	37% 40% 16% 7% 1	2700
	21st to end	Day	30% 39% 14% 10% 6% 1	2700
July	1st to 10th	Day	24% 39% 14% 16% 5% 1	2626
	11th to 20th	Day	19% 40% 18% 19% 4	2619
	21st to end	Day	15% 39% 15% 19% 10% 2	2722
August	1st to 10th	Day	22% 37% 19% 17% 5%	2401
	11th to 20th	Day	19% 38% 17% 14% 10% 2	2298
	21st to end	Day	25% 38% 18% 15% 4 1	2570
September	1st to 10th	Day	18% 39% 15% 18% 9% 1	2160
	11th to 20th	Day	26% 40% 12% 12% 9% 1	2087
	21st to end	Day	33% 38% 11% 12% 6%	1943
October	1st to 10th	Day	31% 38% 14% 12% 5%	1800
	11th to 20th	Day	40% 39% 12% 8% 2	1800
	21st to end	Day	41% 39% 8% 8% 4	1819
November	1st to 10th	Day	43% 41% 8% 4 3	1488
	11th to 20th	Day	43% 42% 7% 7% 1	1520
	21st to end	Day	44% 43% 6% 5% 2	1520
December	1st to 10th	Day	43% 41% 8% 6% 3	1392
	11th to 20th	Day	53% 35% 7% 3 1	1688
	21st to end	Day	61% 28% 6% 4 1	2442
January	1st to 10th	Night	47% 41% 6% 5% 1	2836
	11th to 20th	Night	43% 43% 8% 4 1 1	2730
	21st to end	Night	44% 38% 6% 9% 3	2804
February	1st to 10th	Night	46% 38% 7% 7% 2	2340
	11th to 20th	Night	37% 39% 9% 11% 5%	2274
	21st to end	Night	42% 37% 7% 11% 3	1924
March	1st to 10th	Night	40% 39% 9% 9% 4	2073
	11th to 20th	Night	39% 39% 12% 6% 4	1980
	21st to end	Night	41% 39% 10% 9% 2	2172
April	1st to 10th	Night	39% 39% 11% 10% 2	1800
	11th to 20th	Night	34% 37% 9% 13% 6% 1	1615
	21st to end	Night	35% 38% 11% 11% 5%	1620
May	1st to 10th	Night	32% 38% 11% 16% 3	1445
	11th to 20th	Night	30% 40% 13% 14% 4 1	1416
	21st to end	Night	35% 38% 14% 9% 3	1402
June	1st to 10th	Night	33% 39% 13% 9% 4 2	1260
	11th to 20th	Night	34% 38% 16% 10% 1	1260
	21st to end	Night	26% 40% 14% 13% 5% 2	1260
July	1st to 10th	Night	19% 41% 16% 16% 7% 1	1225
	11th to 20th	Night	15% 39% 18% 21% 6%	1218
	21st to end	Night	12% 38% 14% 23% 11% 3	1353
August	1st to 10th	Night	20% 37% 14% 22% 6%	1510
	11th to 20th	Night	13% 38% 21% 14% 11% 3	1602
	21st to end	Night	22% 39% 17% 20% 3	1785
September	1st to 10th	Night	14% 38% 13% 24% 9% 2	1800
	11th to 20th	Night	25% 39% 10% 12% 11% 2	1872
	21st to end	Night	32% 37% 12% 12% 5% 2	2016
October	1st to 10th	Night	29% 37% 13% 14% 6% 1	2160
	11th to 20th	Night	36% 37% 12% 12% 3	2160
	21st to end	Night	37% 40% 9% 10% 4	2534
November	1st to 10th	Night	42% 41% 8% 6% 2 1	2590
	11th to 20th	Night	42% 41% 9% 6% 2	2660
	21st to end	Night	43% 42% 7% 7% 1	2660
December	1st to 10th	Night	44% 41% 8% 5% 2	2784
	11th to 20th	Night	54% 36% 6% 3 1	3516
	21st to end	Night	59% 27% 7% 6% 1	5214

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	32% 7% 27% 20% 8% 7%	180
	11th to 20th	Day	36% 7% 28% 14% 12% 2	163
	21st to end	Day	28% 7% 25% 23% 12% 4	257
February	1st to 10th	Day	36% 10% 24% 17% 13%	340
	11th to 20th	Day	29% 8% 23% 26% 12% 2	335
	21st to end	Day	23% 13% 26% 24% 11% 3	280
March	1st to 10th	Day	23% 9% 20% 26% 18% 5%	403
	11th to 20th	Day	25% 7% 22% 25% 18% 4	420
	21st to end	Day	26% 6% 23% 27% 15% 4	462
April	1st to 10th	Day	24% 12% 23% 23% 15% 4	420
	11th to 20th	Day	21% 7% 24% 24% 17% 7%	412
	21st to end	Day	20% 8% 22% 27% 19% 5%	420
May	1st to 10th	Day	13% 4 19% 32% 26% 6%	423
	11th to 20th	Day	18% 2 14% 27% 29% 10%	448
	21st to end	Day	13% 3 16% 30% 28% 9%	632
June	1st to 10th	Day	19% 5% 17% 30% 22% 7%	630
	11th to 20th	Day	13% 6% 22% 29% 23% 7%	630
	21st to end	Day	11% 4 15% 33% 27% 10%	630
July	1st to 10th	Day	12% 3 12% 29% 31% 13%	621
	11th to 20th	Day	7% 2 13% 31% 37% 11%	618
	21st to end	Day	4 2 10% 30% 38% 16%	628
August	1st to 10th	Day	9% 4 7% 25% 31% 23%	447
	11th to 20th	Day	5% 2 11% 31% 35% 16%	437
	21st to end	Day	10% 3 15% 31% 32% 9%	495
September	1st to 10th	Day	12% 5% 15% 31% 28% 10%	450
	11th to 20th	Day	19% 4 14% 25% 25% 12%	450
	21st to end	Day	21% 6% 19% 25% 22% 8%	450
October	1st to 10th	Day	24% 5% 16% 24% 20% 10%	450
	11th to 20th	Day	28% 5% 20% 20% 19% 8%	450
	21st to end	Day	27% 10% 23% 23% 13% 4	386
November	1st to 10th	Day	30% 9% 27% 21% 13%	180
	11th to 20th	Day	31% 6% 21% 19% 15% 9%	180
	21st to end	Day	36% 8% 19% 20% 11% 6%	180
December	1st to 10th	Day	36% 11% 18% 17% 12% 6%	180
	11th to 20th	Day	33% 11% 19% 22% 13% 1	180
	21st to end	Day	35% 13% 22% 19% 10%	198
January	1st to 10th	Night	35% 9% 22% 20% 11% 4	850
	11th to 20th	Night	36% 7% 15% 21% 19% 2	810
	21st to end	Night	32% 5% 19% 22% 18% 5%	842
February	1st to 10th	Night	31% 7% 22% 24% 14% 3	720
	11th to 20th	Night	27% 5% 20% 27% 20% 2	704
	21st to end	Night	28% 7% 17% 28% 16% 4	592
March	1st to 10th	Night	23% 6% 21% 26% 17% 6%	720
	11th to 20th	Night	25% 7% 23% 23% 18% 4	720
	21st to end	Night	24% 6% 17% 27% 18% 7%	792
April	1st to 10th	Night	23% 7% 15% 29% 20% 6%	720
	11th to 20th	Night	18% 7% 17% 34% 18% 4	547
	21st to end	Night	23% 5% 19% 31% 18% 5%	540
May	1st to 10th	Night	15% 5% 18% 28% 29% 5%	365
	11th to 20th	Night	16% 4 10% 32% 28% 10%	354
	21st to end	Night	13% 4 16% 32% 27% 7%	389
June	1st to 10th	Night	16% 5% 13% 39% 23% 4	360
	11th to 20th	Night	14% 6% 17% 33% 24% 6%	360
	21st to end	Night	11% 3 13% 34% 32% 7%	360
July	1st to 10th	Night	9% 2 11% 31% 34% 12%	350
	11th to 20th	Night	5% 3 14% 32% 34% 12%	348
	21st to end	Night	4 2 7% 38% 38% 12%	394
August	1st to 10th	Night	9% 1 9% 26% 38% 16%	444
	11th to 20th	Night	6% 2 8% 29% 44% 10%	534
	21st to end	Night	11% 3 13% 31% 34% 8%	597
September	1st to 10th	Night	8% 2 12% 35% 32% 11%	720
	11th to 20th	Night	18% 3 10% 20% 29% 18%	720
	21st to end	Night	23% 3 17% 22% 26% 9%	720
October	1st to 10th	Night	20% 4 14% 25% 28% 8%	720
	11th to 20th	Night	26% 5% 16% 23% 22% 8%	720
	21st to end	Night	28% 6% 20% 26% 16% 4	792
November	1st to 10th	Night	32% 8% 18% 27% 14% 1	740
	11th to 20th	Night	29% 9% 21% 22% 15% 4	760
	21st to end	Night	33% 7% 18% 24% 14% 4	760
December	1st to 10th	Night	32% 8% 16% 22% 18% 4	819
	11th to 20th	Night	37% 8% 23% 21% 10% 1	850
	21st to end	Night	37% 10% 23% 20% 9% 2	935

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