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 2024-11-08.

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	14% 10% 3 9% 6% 5% 5% 4 5% 6% 34%	105557
	Night	16% 11% 4 9% 6% 5% 5% 4 5% 6% 31%	102149
Transparency	Day	49% 5% 17% 21% 8% 1	105301
	Night	55% 4 15% 18% 7% 1	102051
Seeing	Day	19% 6% 18% 26% 23% 8%	15643
	Night	24% 6% 17% 26% 21% 6%	23646

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	25% 17% 5% 11% 7% 6% 4 3 5% 4 12%	2219
	11th to 20th	Day	20% 14% 5% 9% 6% 5% 5% 4 5% 9% 17%	2199
	21st to end	Day	24% 18% 6% 14% 9% 6% 4 4 4 3 7%	2717
February	1st to 10th	Day	19% 16% 5% 11% 8% 6% 5% 5% 6% 6% 14%	1710
	11th to 20th	Day	17% 17% 5% 10% 6% 6% 4 4 5% 5% 20%	1665
	21st to end	Day	14% 15% 5% 10% 8% 5% 6% 5% 5% 7% 18%	1413
March	1st to 10th	Day	11% 16% 4 13% 8% 7% 7% 5% 7% 6% 17%	3286
	11th to 20th	Day	12% 10% 3 10% 7% 5% 5% 4 4 7% 30%	3490
	21st to end	Day	19% 14% 4 10% 6% 6% 6% 3 5% 6% 21%	3843
April	1st to 10th	Day	16% 14% 5% 12% 7% 6% 6% 4 5% 5% 19%	2280
	11th to 20th	Day	14% 13% 5% 10% 8% 7% 5% 4 5% 5% 25%	2421
	21st to end	Day	17% 12% 4 10% 6% 5% 5% 5% 6% 6% 25%	2470
May	1st to 10th	Day	13% 9% 3 7% 5% 5% 4 3 5% 5% 40%	4415
	11th to 20th	Day	11% 7% 2 6% 4 5% 5% 4 7% 11% 38%	4377
	21st to end	Day	20% 11% 3 8% 6% 6% 5% 4 6% 6% 26%	5086
June	1st to 10th	Day	17% 10% 3 8% 7% 7% 6% 4 6% 6% 27%	2850
	11th to 20th	Day	11% 9% 4 10% 7% 6% 7% 5% 7% 8% 26%	2850
	21st to end	Day	10% 7% 4 9% 6% 5% 5% 4 6% 7% 37%	2850
July	1st to 10th	Day	6% 3 1 4 3 2 2 3 3 5% 66%	4740
	11th to 20th	Day	4 3 1 3 2 2 2 2 4 5% 72%	4740
	21st to end	Day	6% 4 2 6% 3 3 4 3 6% 10% 54%	5029
August	1st to 10th	Day	5% 3 1 3 2 2 2 2 4 7% 69%	4247
	11th to 20th	Day	9% 8% 3 8% 4 4 4 4 7% 10% 38%	4026
	21st to end	Day	10% 6% 2 8% 4 4 4 4 5% 8% 44%	4504
September	1st to 10th	Day	9% 5% 2 6% 4 4 5% 4 5% 8% 50%	2280
	11th to 20th	Day	15% 8% 2 7% 4 4 4 4 5% 6% 41%	2202
	21st to end	Day	16% 7% 3 9% 5% 4 4 4 6% 6% 36%	2050
October	1st to 10th	Day	14% 10% 4 12% 7% 5% 4 4 6% 7% 29%	3180
	11th to 20th	Day	21% 8% 3 9% 6% 6% 6% 4 5% 6% 25%	3161
	21st to end	Day	14% 10% 5% 12% 8% 8% 6% 5% 6% 6% 21%	3154
November	1st to 10th	Day	20% 15% 5% 11% 6% 7% 6% 4 4 4 16%	1544
	11th to 20th	Day	18% 15% 4 9% 6% 7% 6% 5% 5% 4 21%	1520
	21st to end	Day	21% 16% 5% 11% 7% 4 6% 4 4 5% 18%	1520
December	1st to 10th	Day	16% 18% 6% 10% 6% 6% 6% 4 4 5% 21%	1392
	11th to 20th	Day	23% 18% 6% 12% 8% 8% 4 3 4 4 10%	1685
	21st to end	Day	23% 17% 5% 13% 8% 6% 5% 4 4 4 12%	2442
January	1st to 10th	Night	20% 20% 5% 12% 7% 6% 5% 4 4 5% 13%	4726
	11th to 20th	Night	22% 12% 4 12% 7% 4 4 4 5% 7% 21%	4699
	21st to end	Night	28% 16% 5% 11% 7% 6% 5% 3 3 4 10%	4940
February	1st to 10th	Night	19% 15% 4 10% 6% 6% 5% 3 5% 5% 21%	2470
	11th to 20th	Night	17% 14% 4 9% 6% 5% 5% 4 4 6% 27%	2402
	21st to end	Night	17% 16% 5% 9% 6% 4 4 4 5% 5% 25%	2041
March	1st to 10th	Night	11% 14% 5% 11% 6% 6% 5% 4 5% 7% 25%	3582
	11th to 20th	Night	9% 8% 2 7% 5% 7% 7% 5% 7% 7% 36%	3489
	21st to end	Night	18% 12% 4 10% 6% 6% 6% 4 4 5% 25%	3810
April	1st to 10th	Night	15% 11% 4 10% 7% 4 6% 5% 6% 8% 25%	1900
	11th to 20th	Night	14% 12% 4 7% 5% 5% 5% 4 6% 7% 31%	1705
	21st to end	Night	15% 10% 4 9% 7% 5% 5% 4 6% 8% 27%	1710
May	1st to 10th	Night	12% 7% 3 7% 5% 4 5% 3 4 5% 47%	2545
	11th to 20th	Night	12% 5% 2 5% 3 4 4 4 7% 10% 45%	2516
	21st to end	Night	18% 10% 3 9% 6% 5% 5% 3 5% 6% 29%	2486
June	1st to 10th	Night	14% 8% 4 9% 6% 4 5% 4 6% 6% 35%	1330
	11th to 20th	Night	12% 8% 4 7% 6% 5% 5% 5% 6% 9% 34%	1330
	21st to end	Night	6% 5% 3 7% 6% 5% 6% 5% 8% 9% 41%	1330
July	1st to 10th	Night	4 4 1 3 3 3 3 3 4 5% 67%	2220
	11th to 20th	Night	3 2 1 2 2 2 2 2 4 6% 74%	2220
	21st to end	Night	6% 3 2 4 3 3 4 5% 6% 7% 58%	2521
August	1st to 10th	Night	3 3 1 3 2 2 2 2 3 6% 73%	2685
	11th to 20th	Night	10% 6% 2 7% 5% 4 5% 4 7% 8% 42%	2812
	21st to end	Night	11% 5% 2 6% 4 5% 4 3 6% 7% 47%	3163
September	1st to 10th	Night	6% 4 2 5% 3 3 3 3 4 7% 60%	1900
	11th to 20th	Night	14% 7% 3 6% 5% 5% 5% 4 5% 6% 41%	1976
	21st to end	Night	15% 8% 3 7% 5% 4 4 4 5% 6% 40%	2129
October	1st to 10th	Night	12% 9% 4 10% 6% 6% 5% 3 4 5% 35%	3800
	11th to 20th	Night	16% 10% 4 10% 6% 6% 5% 4 5% 6% 28%	3777
	21st to end	Night	15% 9% 4 11% 7% 6% 5% 4 6% 7% 28%	4403
November	1st to 10th	Night	22% 12% 4 9% 7% 6% 6% 5% 6% 5% 19%	2694
	11th to 20th	Night	20% 11% 4 10% 7% 6% 5% 3 5% 6% 22%	2660
	21st to end	Night	19% 13% 5% 10% 6% 6% 6% 4 4 5% 20%	2660
December	1st to 10th	Night	17% 16% 5% 10% 7% 7% 5% 4 5% 5% 20%	2784
	11th to 20th	Night	23% 18% 6% 14% 7% 5% 5% 3 4 4 11%	3520
	21st to end	Night	25% 15% 5% 11% 7% 5% 5% 4 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	78% 2 6% 11% 3	2219
	11th to 20th	Day	70% 3 13% 11% 3	2220
	21st to end	Day	83% 2 8% 5% 1	2717
February	1st to 10th	Day	71% 4 10% 9% 4 1	1710
	11th to 20th	Day	65% 5% 12% 13% 4	1674
	21st to end	Day	61% 5% 14% 12% 6% 1	1413
March	1st to 10th	Day	67% 3 9% 14% 7%	3286
	11th to 20th	Day	54% 3 13% 25% 4 1	3490
	21st to end	Day	61% 4 17% 14% 3	3843
April	1st to 10th	Day	61% 6% 15% 14% 5%	2280
	11th to 20th	Day	56% 4 12% 17% 9% 2	2421
	21st to end	Day	54% 4 13% 19% 9% 1	2470
May	1st to 10th	Day	43% 4 17% 26% 10% 1	4415
	11th to 20th	Day	38% 5% 24% 26% 5%	4380
	21st to end	Day	55% 5% 18% 17% 6%	5087
June	1st to 10th	Day	51% 6% 17% 19% 6% 2	2850
	11th to 20th	Day	46% 6% 24% 20% 4 1	2850
	21st to end	Day	40% 6% 23% 22% 8% 1	2850
July	1st to 10th	Day	21% 3 14% 31% 24% 8%	4666
	11th to 20th	Day	15% 3 20% 40% 20% 1	4659
	21st to end	Day	25% 7% 24% 28% 14% 2	4870
August	1st to 10th	Day	16% 3 16% 48% 16% 1	4230
	11th to 20th	Day	36% 9% 30% 17% 8% 1	4065
	21st to end	Day	37% 6% 23% 25% 8%	4503
September	1st to 10th	Day	31% 6% 23% 27% 11% 2	2280
	11th to 20th	Day	45% 4 19% 21% 11% 1	2202
	21st to end	Day	48% 5% 18% 19% 9% 1	2050
October	1st to 10th	Day	54% 6% 16% 20% 5%	3180
	11th to 20th	Day	60% 5% 14% 18% 3	3161
	21st to end	Day	60% 7% 14% 14% 4	3154
November	1st to 10th	Day	68% 5% 12% 10% 4	1544
	11th to 20th	Day	65% 5% 12% 13% 4 1	1520
	21st to end	Day	72% 5% 10% 9% 5%	1520
December	1st to 10th	Day	68% 3 13% 11% 4	1392
	11th to 20th	Day	80% 3 9% 6% 2	1688
	21st to end	Day	78% 3 10% 7% 2	2442
January	1st to 10th	Night	76% 2 10% 9% 4	4726
	11th to 20th	Night	67% 4 15% 10% 3	4740
	21st to end	Night	81% 2 7% 8% 2	4940
February	1st to 10th	Night	66% 4 12% 11% 6% 1	2470
	11th to 20th	Night	59% 4 15% 15% 7%	2404
	21st to end	Night	61% 4 11% 16% 7% 1	2041
March	1st to 10th	Night	61% 2 11% 19% 7%	3582
	11th to 20th	Night	47% 3 16% 28% 5%	3490
	21st to end	Night	64% 3 14% 16% 2	3810
April	1st to 10th	Night	57% 5% 16% 17% 5%	1900
	11th to 20th	Night	52% 5% 13% 20% 9% 2	1705
	21st to end	Night	54% 3 14% 20% 9% 1	1710
May	1st to 10th	Night	42% 3 15% 30% 10%	2545
	11th to 20th	Night	35% 5% 26% 27% 6% 1	2516
	21st to end	Night	58% 3 16% 17% 4 1	2486
June	1st to 10th	Night	49% 5% 18% 20% 7% 2	1330
	11th to 20th	Night	49% 3 22% 20% 5%	1330
	21st to end	Night	39% 5% 23% 24% 7% 2	1330
July	1st to 10th	Night	21% 4 13% 30% 25% 6%	2185
	11th to 20th	Night	14% 3 19% 45% 18% 1	2178
	21st to end	Night	26% 7% 21% 30% 14% 2	2441
August	1st to 10th	Night	16% 2 13% 45% 23% 1	2677
	11th to 20th	Night	38% 8% 29% 16% 8% 2	2839
	21st to end	Night	37% 7% 24% 25% 6% 1	3163
September	1st to 10th	Night	27% 4 21% 33% 13% 3	1900
	11th to 20th	Night	43% 5% 16% 18% 16% 2	1976
	21st to end	Night	46% 4 18% 21% 8% 2	2129
October	1st to 10th	Night	53% 7% 16% 17% 7%	3800
	11th to 20th	Night	56% 5% 16% 20% 3	3777
	21st to end	Night	56% 7% 16% 16% 4	4403
November	1st to 10th	Night	66% 5% 12% 12% 4 1	2694
	11th to 20th	Night	66% 4 13% 11% 5% 1	2660
	21st to end	Night	67% 4 12% 12% 4 1	2660
December	1st to 10th	Night	68% 3 13% 11% 4	2784
	11th to 20th	Night	79% 3 10% 6% 2	3516
	21st to end	Night	75% 2 9% 10% 3	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% 19% 8% 7%	180
	11th to 20th	Day	34% 9% 27% 16% 12% 2	180
	21st to end	Day	30% 9% 25% 21% 11% 4	283
February	1st to 10th	Day	35% 10% 23% 17% 14%	370
	11th to 20th	Day	28% 9% 22% 27% 12% 2	365
	21st to end	Day	22% 14% 25% 24% 12% 3	307
March	1st to 10th	Day	22% 10% 20% 26% 18% 5%	441
	11th to 20th	Day	24% 7% 21% 25% 19% 4	460
	21st to end	Day	26% 6% 23% 26% 15% 4	506
April	1st to 10th	Day	23% 11% 23% 24% 15% 3	460
	11th to 20th	Day	21% 7% 25% 25% 16% 6%	452
	21st to end	Day	20% 8% 22% 27% 18% 5%	460
May	1st to 10th	Day	13% 4 19% 32% 26% 6%	463
	11th to 20th	Day	17% 3 14% 28% 28% 9%	488
	21st to end	Day	15% 3 17% 30% 27% 9%	685
June	1st to 10th	Day	19% 5% 18% 29% 22% 7%	680
	11th to 20th	Day	12% 6% 22% 28% 23% 8%	680
	21st to end	Day	11% 4 15% 33% 26% 10%	680
July	1st to 10th	Day	11% 3 11% 30% 32% 13%	671
	11th to 20th	Day	7% 2 12% 30% 37% 12%	668
	21st to end	Day	5% 2 11% 30% 37% 15%	679
August	1st to 10th	Day	8% 4 7% 24% 32% 25%	487
	11th to 20th	Day	6% 3 11% 29% 34% 17%	477
	21st to end	Day	11% 4 15% 29% 32% 10%	539
September	1st to 10th	Day	11% 5% 13% 30% 28% 12%	490
	11th to 20th	Day	20% 4 14% 25% 26% 11%	490
	21st to end	Day	21% 6% 18% 27% 21% 7%	490
October	1st to 10th	Day	24% 7% 16% 25% 19% 10%	490
	11th to 20th	Day	29% 5% 19% 21% 18% 7%	490
	21st to end	Day	26% 9% 23% 24% 14% 4	420
November	1st to 10th	Day	29% 10% 27% 20% 13%	194
	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	850
	21st to end	Night	34% 5% 19% 21% 17% 4	893
February	1st to 10th	Night	30% 7% 21% 24% 15% 3	760
	11th to 20th	Night	27% 5% 20% 26% 20% 2	744
	21st to end	Night	28% 8% 17% 28% 15% 4	628
March	1st to 10th	Night	22% 7% 21% 26% 17% 6%	760
	11th to 20th	Night	24% 7% 23% 23% 20% 4	760
	21st to end	Night	24% 6% 17% 27% 18% 7%	836
April	1st to 10th	Night	23% 7% 15% 29% 20% 5%	760
	11th to 20th	Night	18% 7% 19% 34% 18% 4	577
	21st to end	Night	23% 5% 18% 31% 18% 5%	570
May	1st to 10th	Night	15% 4 18% 30% 28% 5%	385
	11th to 20th	Night	16% 4 12% 32% 26% 9%	374
	21st to end	Night	14% 4 17% 32% 26% 7%	411
June	1st to 10th	Night	16% 5% 15% 39% 22% 3	380
	11th to 20th	Night	13% 6% 17% 33% 24% 7%	380
	21st to end	Night	11% 3 12% 35% 32% 7%	380
July	1st to 10th	Night	8% 2 12% 33% 34% 11%	370
	11th to 20th	Night	5% 3 13% 33% 35% 12%	368
	21st to end	Night	4 2 7% 38% 37% 12%	416
August	1st to 10th	Night	9% 1 9% 25% 39% 17%	469
	11th to 20th	Night	7% 2 8% 29% 43% 11%	564
	21st to end	Night	11% 3 13% 31% 34% 8%	631
September	1st to 10th	Night	8% 1 11% 34% 34% 12%	760
	11th to 20th	Night	18% 3 11% 20% 29% 18%	760
	21st to end	Night	23% 4 16% 23% 25% 9%	760
October	1st to 10th	Night	20% 4 14% 26% 28% 8%	760
	11th to 20th	Night	26% 4 16% 24% 22% 8%	760
	21st to end	Night	27% 7% 20% 27% 16% 4	836
November	1st to 10th	Night	32% 8% 18% 27% 14% 1	770
	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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